Fibrous structured amorphous silica including precipitated calcium carbonate and compositions of matter made therewith

ABSTRACT

A nano-composite structure. A synthetic nano-composite is described having a first component including a fibrous structured amorphous silica structure, and a second component including a precipitated calcium carbonate structure developed by pressure carbonation. The nano-composite may be useful for fillers in paints and coatings. Also, the nano-composite may be useful in coatings used in the manufacture of paper products.

RELATED PATENT APPLICATIONS

This application is a divisional and claims priority under 35 USC § 121of prior and now pending U.S. patent application Ser. No. 14/262,741filed Apr. 26, 2014, which application claimed priority under 35 USC. §119(e) from U.S. Provisional Patent Application Ser. No. 61/816,649,filed Apr. 26, 2013, entitled FIBROUS STRUCTURED AMORPHOUS SILICAINCLUDING PRECIPITATED CALCIUM CARBONATE, COMPOSITIONS OF MATTER MADETHEREWITH, AND METHODS OF USE THEREOF, the disclosures of each areincorporated herein in their entirety, including the specification,drawing, and claims, by this reference.

STATEMENT OF GOVERNMENT INTEREST

Not Applicable.

COPYRIGHT RIGHTS IN THE DRAWING

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The patent owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

TECHNICAL FIELD

This application relates to novel fillers and pigments, to compositionsof matter including such compositions, and to methods of use of suchcompositions.

BACKGROUND

Fillers and pigments are key components in many industrial markets, suchas paper, paints, plastics, concrete, and pharmaceuticals. Fillers andpigments are utilized to reduce cost, improve functionality, and toimprove the end use performance. One widely used pigment is titaniumdioxide (TiO₂), which is used to provide brightness and light scatteringproperties. Another widely used pigment is fumed silica, which may beadded to some compositions to provide thixotropic attributes, forexample, in paint products. A different product, but with a similarsounding name, is silica fume, which will also be further discussedbelow.

In paper products, commodity filler or pigment products such assynthetic precipitated calcium carbonate (PCC), or ground calciumcarbonate (GCC) are often used. Various forms of PCC used includecalcite crystalline structures, aragonite crystalline structures, andrhombohedral crystalline structures. Such crystalline structures aregenerally characterized by low aspect ratios, moderate brightness, andmoderate light scattering power. Some of such materials provide improvedoptical properties. And, some of such materials enhance desired finishedproduct attributes such as paper strength, when used in paper furnish,or print qualities, when used in paper coatings. However, there remainsa significant need in various paper products for fillers and/or pigmentswhich might improve light scattering power. Similarly, in certain paintproducts, and uses thereof, there remains a need for improved lightscattering power in fillers and/or pigments.

Titanium dioxide is one of the most widely used pigments in manyindustries, such as paints, paper, coatings, and in some composites.Such use may often be to improve brightness, and/or to improve opacity.The property of improved opacity means that light scattering propertiesare improved, which provides a product that is harder to see-through.For example, thin papers may be made more opaque (i.e., made withsee-through properties that make it look as if it were actually thicker)by the use of fillers with opacifying properties. The provision of suchproperties in products using titanium dioxide is primarily due to acombination of characteristics of titanium dioxide, such as a highrefractive index (in the range of from about 2.49 to about 2.61), asmall particle size (often in the 0.2 micron to 0.4 micron size), and inthe manner in which adjacent particles of titanium dioxide pack togetherwhen used in various products. However, despite having a unique shape,size, and crystal structure, titanium dioxide has certain limitations.First, it has a very high density of about 4.2 grams per cubiccentimeter. Further, in order to keep small titanium dioxide particlesfrom agglomerating in various compositions, dispersants must often beused. Such dispersants usually have deleterious effects on strengthproperties, especially in the case of coated paper. Also, titaniumdioxide particles are highly abrasive. Finally, due to the complexity ofsome widely used titanium dioxide manufacturing processes, which mayinclude complex separation and purification processes, titanium dioxideis one of the most expensive fillers and/or coating pigments currentlyavailable.

Another filler and/or pigment that may be utilized in some applicationsis fumed silica. Fumed silica (also called pyrogenic silica) isgenerally manufactured from flame pyrolysis of silicon tetrachloride, orby the vaporization of quartz in a 3000° C. arc furnace. The primaryparticle surface area of most fumed silica is broadly in the range offrom about 50 to about 600 square meters per gram. Furthermore,amorphous fumed silica particles may be fused into chainlike secondaryparticles which, in turn, agglomerate into tertiary 3-dimensionalparticles. One limitation of fumed silica material is that it isnon-porous. Also, fumed silica is generally highly thixotropic, andconsequently may cause high viscosity compositions, for example whenadded to paints and coatings. Also, the environmental impacts of themanufacturing processes for fumed silica, and the usually high cost offumed silica, limit its use.

Silica fume (also called micro-silica, and not to be confused with thejust discussed fumed silica) is an amorphous (i.e., non-crystalline)material. Silica fume is often collected as an ultra-fine powder as aby-product of silicon or ferro-silicon alloy production. Silica fume isgenerally in the form of spherical particles with an average particlesize of about 150 nanometers. Silica fume has a surface area in therange of from about 15 to about 30 square meters per gram. Also, silicafume is a highly pozzolinic material, and thus may be used in cement andconcrete to enhance compressive strength, bond strength, and abrasionresistance. However, at this time, silica fume, being a byproduct ofproduction of other materials, is in relatively short supply.

With respect to the manufacture of amorphous silica compounds, U.S. Pat.No. 4,230,765, issued Oct. 28, 1980 to Takahashi et al., for NOVELAMORPHOUS SILICA, and PRODUCTS THEREOF, describes methods formanufacture of various types of amorphous silica compounds from calciumsilicate hydrates. However, he did not develop products of size and ofcertain characteristics to provide suitable performance for use in highperformance paper coatings of that are described herein. Further, he didnot recognize that by carefully controlling the reaction conditions,fixation of calcium carbonate phases to an amorphous silica substratecould be selectively determined, and in so doing, enhance propertiesprovided by such products, especially for high performance paper coatingcompositions.

In summary, the just discussed fillers and/or pigments are generally oflimited purpose. In many applications, each may have a single or limitednumber of product enhancing properties. Thus, there remains an as yetunmet need for a multi-functional filler and/or pigment that may, inmany applications, replace expensive fillers and pigments such astitanium dioxide, fumed silica, or silica fume. It would be advantageousif such a new filler and/or pigment provided a combination of at leastsome ideal properties, such as (1) high surface ratio, (2) high aspectratio, (3) high brightness, and (4) high light scattering coefficient.And, it would be even more advantageous if such a multi-functionalfiller and/or pigment were environmentally safe, and available at pricescompetitive with expensive fillers such as titanium dioxide, fumedsilica, or silica fume. Consequently, it is believed that provision of aunique multi-functional filler and/or pigment would be an interestingand significant contribution to the art and science of fillers andpigments.

BRIEF DESCRIPTION OF THE DRAWING

Various aspects of the developments described herein will be describedby way of exemplary embodiments, illustrated in the accompanying drawingfigures in which like reference numerals denote like elements, and inwhich:

FIG. 1 is a diagram released by PIRA International in November 2005titled The Nanotechnology Marketplace; the diagram indicates variousindustries that may benefit from nanotechnology, and lists some of thekey areas in which research is being conducted as regards nanomaterials.

FIG. 2 is a photograph, as seen through a scanning electron microscopeat a 2000 times magnification, of a novel nano-composite materialincluding a fibrous pillow or haystack structure having interstitialspaces between at least some of the adjacent fibers of nano-structuredamorphous silica, and having a nano-fibrous crystalline aragonite phaseof precipitated calcium carbonate therein or thereon, or protrudingtherefrom (together the nano-composite material may be described usingthe abbreviation “SAS & FCA”), made as described herein, showingelongated “needle” shaped crystals at the center and bottom of thepicture which are fibrous crystalline aragonite, while the shapes in theupper right corner and along the right side of the picture includeprimarily a structured amorphous silica product in a haystackconfiguration that presents a fibrous appearance having interstitialspaces between adjacent fibrous elements.

FIG. 3 is a graph of an X-ray diffraction (XRD) scan of the sample justshown in FIG. 2 above, along with scans of control compounds includingcalcite, tobermorite, xonotlite, and aragonite; the data indicates thatthe sample includes XRD peaks at the same locations as the aragonitecrystalline sample, with a minor amount of tobermorite crystals.

FIG. 4 is a photograph taken by a scanning electron microscope (SEM) at2000 times magnification of an embodiment for a synthetic nano fibrouscalcium silicate hydrate (CSH) in the form of a synthetic xonotlite. Thexonotlite was produced to serve as a replaceable substrate in theproduction of a novel nano-composite (SAS & FCA) material as describedherein. The circled area shows a secondary porous macro structure of thematerial that in this embodiment is about 20 microns by 40 microns insize, and which is provided in a haystack configuration that presents afibrous appearance having interstitial spaces between adjacent fibrouselements.

FIG. 5 is the graph of the results from an X-ray diffraction (XRD) scanof a sample of the xonotlite material shown in FIG. 4, together withscans of control materials including calcite crystals, tobermoritecrystals, xonotlite crystals and aragonite crystals. The scan indicatesthat the sample material includes XRD peaks at the same locations asxonotlite crystals.

FIG. 6 is a photograph taken in a scanning electron microscope (SEM) at2000 times magnification of a sample of a composite nano structuredcomposite (SAS & FCA) including both amorphous silica and nano fibrouscrystalline aragonite, and made by a process described herein; thematerial in the small oval is a fibrous crystalline aragonite, while thematerial in the large circle includes a structured amorphous silica thathas been built utilizing the replaceable substrate xonotlite as depictedin FIG. 4 above.

FIG. 7 is a graph of the X-ray diffraction (XRD) scan of a sample of aunique nano-composite material (SAS & FCA) shown in FIG. 6, along withscan of some controls including calcite, tobermorite, xonotlite, andaragonite; this XRD data indicates that the sample material includespeaks at the same locations as aragonite crystals.

FIG. 8 is a graph showing the surface areas of different phases (i.e.,the different forms, namely foshagite, xonotlite, tobermorite, andriversidite) of calcium silicate hydrates; the surface area measurementsshown (expressed as m²/gm) were obtained using the BET(Brunauer-Emmet-Teller) method (see S. Brunauer, P. H. Emmett and E.Teller, J. Am. Chem. Soc., 1938, 60, 309).

FIG. 9 is a graph which shows the surface areas (BET measurements) ofnano fibrous calcium silicate hydrates (CSH) against two commonmacro-sized mineral pigments, namely precipitated calcium carbonate(PCC) and titanium dioxide (TiO₂); macro represents riversidite, microrepresents xonotlite, and nano represents foshagite.

FIG. 10 is a graph which shows the relative aspect ratio of nano fibrouscalcium silicate hydrates (CSH) against two common macro-sized mineralpigments, namely precipitated calcium carbonate (PCC) and titaniumdioxide (TiO₂); macro represents riversidite, micro representsxonotlite, and nano represents foshagite.

FIG. 11 is a graph showing the relative bulk densities (in pounds percubic foot) of nano fibrous calcium silicate hydrates (CSH) againstvarious papermaking materials, namely pulp fibers, precipitated calciumcarbonate (PCC), and titanium dioxide (TiO₂).

FIG. 12 is a photograph taken using a scanning electron microscope (SEM)at 2000 times magnification, of a calcium silicate hydrate, namelyriversidite.

FIG. 13 is a graph of an X-ray diffraction (XRD) scan of a sample of theriversidite material just illustrated in FIG. 12; the two major XRDpeaks for the riversidite material are labeled for easy reference.

FIG. 14 is a photograph taken using a scanning electron microscope (SEM)at 2000 times magnification of another calcium silicate hydrate, namelyfoshagite.

FIG. 15 is a graph of the X-ray diffraction (XRD) scan of a sample ofthe material just shown in FIG. 14; the major XRD peaks for thisfoshagite material are labeled for easy reference.

FIG. 16 is a photograph taken using a scanning electron microscope (SEM)at 2000 times magnification of another fibrous calcium silicate hydrate,namely tobermorite.

FIG. 17 is a graph of the X-ray diffraction (XRD) scan of a sample ofthe tobermorite material shown in FIG. 16, in which the major XRD peaksfor tobermorite are labeled for easy reference; note that the major XRDpeaks for riversidite also appeared in this XRD scan, and thus the majorXRD peaks for riversidite are also included and labeled accordingly.

FIG. 18 is a photograph taken using a scanning electron microscope (SEM)at 2000 times magnification, illustrating another fibrous calciumsilicate hydrate, namely xonotlite.

FIG. 19 is a graph of the X-ray diffraction (XRD) scan of a sample ofthe material shown in FIG. 18; the major XRD peaks for xonotlite arelabeled for easy reference.

FIG. 20 is a photograph taken using a scanning electron microscope (SEM)at 2000 times magnification of foshagite crystals; note that the primarystructure shows nano-fibers while a secondary structure providesnano-fibers agglomerated into a “hollow” or porous macro-sphericalstructure having interstitial spaces between adjacent fibers.

FIG. 21 shows a photograph taken using a scanning electron microscope(SEM) at 10000 times magnification of precipitated aragonite phasecalcium carbonate crystals made by a pressure carbonation technique asmore fully described herein below.

FIG. 22 shows a photograph taken using a scanning electron microscope(SEM) at 10000 times magnification of precipitated scalenohedral phasecalcium carbonate crystals made by a pressure carbonation technique asmore fully described herein below.

FIG. 23 shows a photograph taken using a scanning electron microscope(SEM) at 10000 times magnification of unique rhombohedral phase calciumcarbonate crystals made by a pressure carbonation technique as morefully described herein below.

FIG. 24 shows a photograph taken using a scanning electron microscope(SEM) at 40000 times magnification of unique nano-rhombohedral phasecalcium carbonate crystals made by a pressure carbonation technique asmore fully described herein below; note that the primary particlesagglomerate into secondary structures of from about 1 micron to about 2microns in size.

FIG. 25 provides a basic process flow diagram describing the sequence ofprimary reactions which may be useful for the manufacture of anano-composite material that includes both nano-fibrous crystallinearagonite and nano-structured amorphous silica.

FIG. 26 shows a photograph taken using a scanning electron microscope(SEM) at 2000 times magnification of a synthetic calcium silicatehydrate in the xonotlite phase, showing macro structured fibrousparticles having interstitial spaces between adjacent fibers, and whichmay be selected as an exemplary raw material to serve as replaceablesubstrate in the manufacture of a novel nano-composite material thatincludes both nano-structured amorphous silica (“SAS”) and nano-fibrouscrystalline aragonite (“FCA”), which novel nano-composite material maybe identified herein as “SAS & FCA”.

FIG. 27 shows a graph of an X-ray diffraction (XRD) scan of a sample ofthe unique material just shown in FIG. 26 (designated as sample materialT7-1200), along with some standard control materials including calcite,aragonite, tobermorite, and xonotlite; note that the data indicates thatthe sample material includes peaks at the location of major XRD peaks ofxonotlite, with a minor amount of tobermorite.

FIG. 28 shows a photograph taken using a scanning electron microscope(SEM) at 18273 times magnification of a synthetic nano-fibrous calciumsilicate hydrate in the xonotlite phase, which may be selected as auseful raw material in the manufacture of a nano-composite containing astructured amorphous silica and a fibrous calcium carbonate crystal in aselected phase such as aragonite.

FIG. 29 shows a graph of an X-ray diffraction (XRD) scan of a sample ofthe calcium silicate hydrate material just illustrated in FIG. 28, alongwith two other standard control materials, namely xonotlite and calcite;note that the sample material includes peaks at the location of majorXRD peaks of xonotlite.

FIG. 30 shows a photograph taken using a scanning electron microscope(SEM) at 5124 times magnification of a sample of a novel, uniquenano-composite material containing structured amorphous silica (“SAS”)and a fibrous calcium carbonate in a selected phase, namely aragonite(“FCA”), together designated using the abbreviation “SAS & FCA”, as maybe manufactured according to the instructions set forth herein.

FIG. 31 shows a graph of an X-ray diffraction (XRD) scan of a sample ofa novel, unique nano-composite material (SAS & FCA) as shown anddescribed in FIG. 30, along with two other standard control materials,namely aragonite and calcite; note that this graph indicates that thenano-composite material (SAS & FCA) includes peaks at the same locationsthe major XRD peaks of aragonite.

FIG. 32 shows a photograph taken with a scanning electron microscope(SEM) at approximately 15000 times magnification of a syntheticnano-fibrous calcium silicate hydrate in the foshagite phase, which maybe useful as a raw material in the manufacture of nano-compositematerials as further set forth herein below; note, however, the scaleindicated at the bottom is not correct and the correct scale length(rather than 0.005 pm) should actually indicate two (2) microns.

FIG. 33 shows a graph of an X-ray diffraction (XRD) scan of a sample ofthe material just illustrated in FIG. 32, along with other controlmaterials, namely xonotlite and foshagite; note that this data indicatesthat the sample material includes major XRD peaks at the same locationsas both xonotlite and foshagite.

FIG. 34 shows a photograph taken using a scanning electron microscope(SEM) at 19591 times magnification of a sample of a nano-structuredcomposite material that includes nano-fibrous structured amorphoussilica (“SAS”) and nano-fibrous precipitated calcium carbonate in thearagonite phase (“FCA”), which novel nano-composite material (SAS & FCA)was made according to process(s) set forth herein.

FIG. 35 shows a graph of the X-ray diffraction (XRD) scan of thenano-structured composite material (SAS & FCA) just shown and describedin FIG. 34, along with two standard control materials, namely aragoniteand calcite; note that the data indicates that the sample includes majorXRD peaks at the same locations as aragonite.

FIG. 36 is a graph illustrating an example where substitution of a novelnano-composite material (SAS & FCA) as described herein for a majorportion (e.g., 75%) of the conventionally utilized titanium dioxide(TiO₂) has the effect of increasing a viscosity of the coatingformulation.

FIG. 37 is a graph illustrating various examples where the use of anovel nano-composite material (SAS & FCA) is described in substitutionfor various portions (e.g., 12.5%, 25%, 37.5%, and 50%) ofconventionally utilized titanium dioxide (TiO₂) in coating formulations,showing the effect on immobilization of the coating's pigments; notethat as tested and illustrated, the shorter the time elapsed until peakviscosity, the better the immobilization of pigments in the coating, inaccord with a dynamic water retention (DWR) test as is known to those ofskill in the art in the paper industry.

FIG. 38 is a graphical representation of the effect on IGT pick testresults (see ISO 3783 or TAPPI Standard 514, or a web site explanationshown at http://www.appliedpapertech.com/igt.html), when conventionallyutilized titanium dioxide (TiO₂) is replaced (at 25%, 50%, and 75%replacement levels) by a novel nano-composite material (SAS & FCA) asdescribed herein, in unbleached top coat formulations used on acalendared unbleached board paper product.

FIG. 39 is a graphical representation of the effect on IGT blister testresults, when conventionally utilized titanium dioxide (TiO₂) isreplaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in anunbleached top coat formulation used on a calendared unbleached boardpaper product.

FIG. 40 is a graphical representation of the effect on the APTappearance test results, when conventionally utilized titanium dioxide(TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in unbleachedtop coat formulations used on a calendared unbleached board paperproduct; note that a smaller APT appearance test result number indicatesa more uniform appearance, which is desirable on calendared unbleachedboard.

FIG. 41 is a graphical representation of the effect on ISO Brightnesstest results, when conventionally utilized titanium dioxide (TiO₂) isreplaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in unbleachedtop coat formulations used on a calendared unbleached board paperproduct.

FIG. 42 is a graphical representation of the effect on Parker PrintRoughness test results (at 10 S), when conventionally utilized titaniumdioxide (TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) bya novel nano-composite material (SAS & FCA) as described herein, inunbleached top coat formulations used on a calendared unbleached boardpaper product.

FIG. 43 is a graphical representation of the effect on Hunter “L” orWhiteness test results, when conventionally utilized titanium dioxide(TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in unbleachedtop coat formulations used on a calendared unbleached board paperproduct.

FIG. 44 is a graphical representation of the effect on Hunter “a” or“red-green” test results, when conventionally utilized titanium dioxide(TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in unbleachedtop coat formulations used on a calendared unbleached board paperproduct; note that a positive value indicates a reddish color, while anegative value indicates a more desirable greenish color.

FIG. 45 is a graphical representation of the effect on Hunter “b” or“yellow-blue” test results, when conventionally utilized titaniumdioxide (TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) bya novel nano-composite material (SAS & FCA) as described herein, inunbleached top coat formulations used on a calendared unbleached boardpaper product; note that a positive value indicates a yellowish color,while a negative value indicates a more desirable blue-white color.

FIG. 46 is a graphical representation of the effect on gloss testresults, in the machine direction (“MD”) when conventionally utilizedtitanium dioxide (TiO₂) is replaced (at 25%, 50%, and 75% replacementlevels) by a novel nano-composite material (SAS & FCA) as describedherein, in unbleached top coat formulations used on a calendaredunbleached board paper product.

FIG. 47 is a graphical representation of the effect on gloss testresults in the cross direction (“CD”) when conventionally utilizedtitanium dioxide (TiO₂) is replaced (at 25%, 50%, and 75% replacementlevels) by a novel nano-composite material (SAS & FCA) as describedherein, in unbleached top coat formulations used on a calendaredunbleached board paper product.

FIG. 48 is a graphical representation of the effect on the caliper of asample paper product, when conventionally utilized titanium dioxide(TiO₂) is replaced (at 25%, 50%, and 75% replacement levels) by a novelnano-composite material (SAS & FCA) as described herein, in unbleachedtop coat formulations used on a calendared unbleached board paperproduct.

FIG. 49 is a graphical representation of the effect on IGT Pick testresults when all of the conventionally utilized titanium dioxide (TiO₂)and coating clays are replaced (i.e., 100% replacement level) by a blendof (a) novel nano-composite material (SAS & FCA) as described herein and(b) an aragonite phase form of Super Precipitated Calcium Carbonate(“S-PCC” as further described herein below, and also see Table 27), inunbleached base and top coat formulations used on a calendaredunbleached board paper product.

FIG. 50 is a graphical representation of the effect on IGT Blister Testresults, when all of the conventionally utilized titanium dioxide (TiO₂)and coating clays are replaced (i.e., 100% replacement level) by a blendof (a) novel nano-composite material (SAS & FCA) as described herein and(b) by aragonite Super Precipitated Calcium Carbonate (“S-PCC”), inunbleached base and top coat formulations used on a calendaredunbleached board paper product; also see Table 27.

FIG. 51 is a graphical representation of the effect on APT Appearancetest results, when all of the conventionally utilized titanium dioxide(TiO₂) and coating clays are replaced (i.e., 100% replacement level) bya blend of (a) novel nano-composite material (SAS & FCA) as describedherein and (b) by aragonite Super Precipitated Calcium Carbonate(“S-PCC”), in unbleached base and top coat formulations used on acalendared unbleached board paper product; see Table 27.

FIG. 52 is a graphical representation of the effect on ISO Brightnesstest results, when all of the conventionally utilized titanium dioxide(TiO₂) and coating clays are replaced (i.e., 100% replacement level) bya blend of (a) novel nano-composite material (SAS & FCA) as describedherein and (b) aragonite Super Precipitated Calcium Carbonate (“S-PCC”),in unbleached base and top coat formulations used on a calendaredunbleached board paper product; also see Table 27.

FIG. 53 is a graphical representation of the effect on Hunter “L” ValueWhiteness test results, when all of the conventionally utilized titaniumdioxide (TiO₂) and coating clays are replaced (i.e., 100% replacementlevel) by a blend of (a) novel nano-composite material (SAS & FCA) asdescribed herein, and (b) aragonite Super Precipitated Calcium Carbonate(“S-PCC”), in unbleached base and top coat formulations used on acalendared unbleached board paper product; see Table 27.

FIG. 54 is a graphical representation of the effect on Hunter “a” Valueor “red-green” test results, when all of the conventionally utilizedtitanium dioxide (TiO₂) and coating clays are replaced (i.e., 100%replacement level) by a blend of (a) novel nano-composite material (SAS& FCA) as described herein, and (b) by pressure carbonated aragonite(Super Precipitated Calcium Carbonate, or “S-PCC”), in unbleached baseand top coat formulations used on a calendared unbleached board paperproduct; note that a positive value indicates a reddish color, while anegative value indicates a more desirable greenish color; also see Table27.

FIG. 55 is a graphical representation of the effect on Hunter “b” or“yellow-blue” test results, when all of the conventionally utilizedtitanium dioxide (TiO₂) and coating clays are replaced (i.e., 100%replacement level) by a blend of (a) novel nano-composite material (SAS& FCA) as described herein and (b) aragonite S-PCC, in unbleached baseand top coat formulations used on a calendared unbleached board paperproduct; note that a positive value indicates a yellowish color, while anegative value indicates a more desirable blue-white color; also seeTable 27.

FIG. 56 is a graphical representation of the effect on TAPPI Opacitytest results when all of the conventionally utilized titanium dioxide(TiO₂) in a coating used on high basis weight label stock is replaced(i.e., 100% replacement level), (a) by a novel nano-composite material(SAS & FCA) as described herein in combination with another calciumsilicate hydrate product (condition 1), or (b) by a calcium silicatehydrate and aragonite (condition 2), or (c) by a calcium silicatehydrate alone (condition 3).

FIG. 57 is a graphical representation of the effect on ISO Opacity testresults when all of the conventionally utilized titanium dioxide (TiO₂)in a coating used for high basis weight label stock is replaced (i.e.,100% replacement level), (a) by a novel nano-composite material (SAS &FCA) as described herein in combination with another calcium silicatehydrate product (condition 1), or (b) by a calcium silicate hydrate andaragonite (condition 2), or (c) by a calcium silicate hydrate alone(condition 3).

FIG. 58 is a graphical representation of the effect on TAPPI Opacitytest results with respect to coating formulations used on low basisweight label stock, when the total amount of conventionally utilizedtitanium dioxide (TiO₂) in a coating used for low basis weight labelstock is partially or totally replaced, (a) by the combination of (1) anovel nano-composite (SAS & FCA) as described herein with (2) a calciumsilicate hydrate and (3) ground calcium carbonate (GCC)—with no titaniumdioxide used—(condition 1), or (b) by using only 50% of the usualtitanium dioxide in combination with a calcium silicate hydrate,aragonite, and ground calcium carbonate (condition 2); or (c) by usingonly 50% of the usual titanium dioxide in combination with a calciumsilicate hydrate and aragonite (condition 3).

FIG. 59 is a graphical representation of the effect on TAPPI Opacitytest results with respect to coating formulations used on low basisweight label stock, when some of the conventionally utilized titaniumdioxide (TiO₂) in a coating used for low basis weight label stock isreplaced (a) by using only 50% of the usual titanium dioxide incombination with a calcium silicate hydrate, a novel nano-composite (SAS& FCA) as described herein, and ground calcium carbonate (condition 1),or (b) by using only 50% of the usual titanium dioxide in combinationwith a calcium silicate hydrate, aragonite, and ground calcium carbonate(condition 2), or (c) by using only 50% of the usual titanium dioxide incombination with a calcium silicate hydrate and aragonite (condition 3).

FIG. 60 is a graph of the energy dispersive spectroscopy (“EDS”)analysis provided by EDAX Corporation of the unique nano-compositematerial (SAS & FCA) containing structured amorphous silica (“SAS”) anda fibrous calcium carbonate in a selected phase, namely aragonite(“FCA”).

In the various figures of the drawing, like features may be illustratedwith the same reference numerals, without further mention thereof.Further, the foregoing figures are merely exemplary, and may containvarious elements that might be present or omitted from actualimplementations of various embodiments depending upon the circumstances.An attempt has been made to provide the figures in a way thatillustrates at least those elements that are significant for anunderstanding of the various embodiments and aspects of the developmentsdescribed herein. However, various other elements for a multi-functionalfiller and/or pigment, especially as applied for various compositionsusing the same, may be utilized in order to provide useful, reliable,and highly functional fillers and/or pigments.

SUMMARY

I have now developed a novel, multi-functional, nano-composite filler.The filler includes a synthetic fibrous structured amorphous silica(“SAS”) component and a nano-fibrous crystalline aragonite precipitatedcalcium carbonate (“FCA”) component, which together may be abbreviatedas a “SAS & FCA” nano-composite. In an embodiment, such a nano-compositefiller maybe characterized as having high surface area (from about 40 toabout 200 meters squared per gram). In an embodiment, when mixed withwater, such a nano-composite filler and water mixture results in a pH ina relatively neutral range of from about 6.5 to about 7.5. In anembodiment, such unique nano-composites (SAS & FCA) may have a highwater absorption rate, for example in the range of from about 100% toabout 300%. In an embodiment, such unique nano-composites (SAS & FCA)may have a high oil absorption rate, for example in the range of fromabout 150% to about 300%.

In an embodiment, as shown in FIG. 2, a nano-composite SAS & FCAmaterial may include at least two distinct components. As shown in FIG.2, a first component having a globular, haystack, or pillow shapedstructure may be provided. The globular, haystack, or pillow shapedstructure may be provided in a configuration that presents a fibrousinterstitial appearance, having inner layers and outer layers withirregular interlacing fibers or filaments which are fixed and disposedin relation to each other wherein the interlacing fibers or filaments ofat least some of said inner layers are visible to a greater or lessdegree through the interstices of said outer layers, when said fibrousstructure is viewed via microscope. In an embodiment, such globular orhaystack or pillow shaped structure may be sized from about ten (10)microns to about forty (40) microns in size. In an embodiment, suchglobular “hay stack” type structure may be composed of “hair” likenano-fibers of amorphous silica, each having a selected diameter and aselected length. In an embodiment, the diameter of such amorphous silicafibers of may be in the ten (10) nanometer (nm) range. In an embodiment,the amorphous silica fibers may be in the range of from about three (3)to about four (4) microns in length. In an embodiment, the aspect ratioof such amorphous silica nano-fibers may be approximately 100:1.

In an embodiment, a second component may be provided in a nano-composite(SAS & FCA) material. In an embodiment, a second component may beprovided as an aragonite crystal. In an embodiment, such an aragonitecrystal may have a “needle” shaped fiber structure. In an embodiment, orin various embodiments, such aragonite crystals may have an estimateddiameter of from about 100 nm to about 200 nm. In an embodiment, or invarious embodiments, such aragonite crystals may have a length of fromabout 3 microns to about 10 microns.

In summary, a novel nano-composite material is described herein. Suchnano-composite material includes a synthetic fibrous structuredamorphous silica component (the “SAS” component), and a nano-fibrouscrystalline precipitated calcium carbonate in the aragonite phasecomponent (the “FCA” component). As set forth in the drawing figures, anX-ray diffraction pattern (XRD) analysis of the unique nano-compositematerial identified only a single crystalline constituent, which matchedthe X-ray diffraction (XRD) pattern of an aragonite precipitated calciumcarbonate (see FIG. 3), with major peaks at 3.276, 3.398, and 1.977D-spacing (angstroms). Thus the first structure is amorphous silica,rather than a crystalline calcium silicate hydrate. Further, as noted inFIG. 60, an EDAX analysis confirmed the first component to be silica.Thus, the unique nano-composite material described herein includes firstcomponent of amorphous silica, and a second component of crystallinearagonite.

Further, the nano-composite (SAS & FCA) is believed useful as filler,for example, in paints and coatings. And, initial tests have indicatedthat the nano-composite (SAS & FCA) material is useful as a component ofcoating compounds, especially in the manufacture of paper and paperproducts. A myriad of uses may be developed, based on the uniqueproperties of such synthetic nano-composite (SAS & FCA) materials, asindicated in evaluations thus far conducted.

The foregoing briefly describes a novel, unique nano-composite thatincludes a first component of amorphous silica, and a second componentof aragonite crystals. As described herein, such aragonite crystals mayadvantageously be synthesized by way of pressure carbonation technique.However, the various objectives, features and advantages of the novelnano-composite materials described herein will be more readilyunderstood upon consideration of the following detailed description,taken in conjunction with careful examination of the accompanyingfigures of the drawing.

DETAILED DESCRIPTION

A unique nano-composite material has been developed which includes both(a) nano-fibrous structured amorphous silica (SAS) and (b) nano-fibrouscrystalline aragonite precipitated calcium carbonate (FCA). Thus, thisnovel nano-composite material may be referred to herein by theabbreviation “SAS & FCA”. In one aspect, the SAS & FCA nano-compositematerial may be characterized by having high surface area (approximately40 to 200 m²/gram). The pH of the SAS & FCA nano-composite material,when mixed with water, is generally in the neutral range of from about6.5 to about 7.5. In an embodiment, an SAS & FCA nano-composite materialmay have very high water absorption, and very high oil absorptionability, in the range of from about 100% to about 300% for waterabsorption, and from about 150% to about 300% for oil absorption. Asseen in FIG. 2, a scanning electron microscope (SEM) picture clearlyshows two distinct components for a SAS & FCA nano-composite material.The first components (an example is seen prominently at the upper right)are globular or haystack or pillow shaped structures, which may in anembodiment be from approximately 10 microns to approximately 40 micronsin size. Such first components includes “hair like” nano-fibers, whichin an embodiment may be approximately 10 nanometers (nm) in diameter. Inan embodiment, those hair like nano-fibers may be from about 3 micronsto about 4 microns in length. An energy dispersive x-ray spectroscopy(“EDAX”) analysis confirmed the presence of SiO₂ in such hair likenano-fibers. As also seen in FIG. 2, the second components are “needle”shaped fiber like structures with an estimated diameter (but not limitedthereto) of from about 100 nm to about 200 nm and with a lengthgenerally ranging in size (but not limited thereto) from about 3 micronsto about 10 microns. As shown in FIG. 3, it is significant to note thatthe X-Ray Diffraction pattern (XRD) analysis identified only a singlecrystalline component, which matched the XRD pattern of a precipitatedcalcium carbonate in the aragonite phase (see FIG. 3) with major peaksat 3.276, 3.398, and 1.977 D-spacing (in angstroms). Such analysisconfirms that in an embodiment, the nano-composite material describedherein may include structured amorphous silica (SiO₂) and fibrouscrystalline aragonite carbonate. Consequently, it can be appreciatedthat the substances comprising the structures provided by selectedprecursor crystalline calcium silicate hydrates (“CSH”)—such asxonotlite—react and are converted substantially in place into amorphoussilica. Thus, precursor crystalline calcium silicate hydrates may, underconditions described herein, be replaced by amorphous silica. Thus, theamorphous silica structures, and the associated fibrous crystallinecalcium carbonate structures which is in an aragonite phase, areproduced as a nano-composite material. In further detail, the structureof the nano-composite SAS & FCA material includes an amorphous silicaportion having a haystack or pillow shaped configuration that presents afibrous interstitial appearance, having inner layers and superimposedouter layers with irregular interlacing fibers or filaments which arefixed and disposed in relation to each other wherein the interlacingfibers or filaments of at least some of the inner layers of thestructured amorphous silica are visible to a greater or less degreethrough the interstices of outer layers of the structured amorphoussilica, when the nano-composite material is viewed via scanning electronmicroscope. Further, the crystalline calcium carbonate portion includescrystalline aragonite structures built within, or on, or within and on,or at least in part extending from, the amorphous silica portion of thenano-composite material. Thus, in an embodiment, the just described“nano-composite” material simultaneously provides certaincharacteristics that enable filler and/or pigment performance both ofamorphous silica and of a crystalline calcium carbonate in an aragonitephase, as will be further understood below in relation to examplesprovided.

Method for Manufacture—Starting Materials and the Process

In an embodiment, one unique aspect of the developments described hereinmay involve the use of various phases of synthetic calcium silicatehydrates (CSH) and the use of carbon dioxide (CO₂) under pressure, tomanufacture a nano-composite material including both (a) amorphoussilica and (b) fibrous crystalline calcium carbonate (which in anembodiment is provided in the aragonite phase).

FIG. 4 provides an SEM photograph crystalline xonotlite, of one of thecalcium silicate hydrate (CSH) starting materials that may be utilizedfor producing a nano-composite SAS & FCA as described herein. The SEMphotograph shows secondary particles ranging from about 10 microns toabout 40 microns. In an embodiment, the secondary particles may be madeup of nano-fibers of approximately 10 nm in diameter. In an embodiment,the secondary particles may be made up of nano-fibers of from about 3microns to about 4 microns in length. In an embodiment, the secondaryparticles may be made up of nano-fibers having an aspect ratio of about100:1. Such starting material may be further identified by the graph ofthe XRD analysis shown in FIG. 5. There, the materials is seen to have amajor XRD peak at 3.22 angstroms and minor peaks at 2.04 and 8.50angstroms, which conforms to the characteristics of a xonotlite crystal.While other types of calcium silicate hydrates may be used tomanufacture a nano-composite material as described herein (e.g.,riversidite, or tobermorite, or foshagite), at the present time, it isbelieved that the conversion efficiency may be higher when using axonotlite phase calcium silicate hydrate.

A novel development described herein is a process to convert acrystalline silicate hydrate such as xonotlite into amorphous silica. Inan embodiment, such conversion may be achieved while concurrentlyproducing a synthetic crystalline calcium carbonate in the aragonitephase. Such a process may involve the reaction of xonotlite with carbondioxide (CO₂) under pressure, and thus may generally be referred to as aprocess for pressure carbonation of nano-fibrous calcium silicatehydrates. The SEM photograph and XRD patterns of the carbonated productresulting from reaction with xonotlite calcium silicate hydrate as astarting material are given in FIGS. 6 and 7 respectively. Here again,the SEM photograph shows two distinct components in the nano-compositematerial, namely amorphous silica (within the solid circle) and fibrouscrystalline aragonite calcium carbonate (within the dashed oval). Inspite of the appearance of the structures, the XRD of the nano-compositematerial identifies only a single crystalline phase, namely aragonitephase calcium carbonate.

In one aspect, the process described herein includes the use of seedmaterials for enhancement of reactions, as such materials may promoteconversion efficiency. The efficiency of a pressure carbonation processmay be enhanced by using seed materials and/or promoters or catalysts,such as pre-formed amorphous silica, which may be provided with, orwithout the use of an aragonite crystal. In an embodiment, reactionpromoters and/or catalysts may include calcium hydroxide, and/ormagnesium hydroxide.

Another aspect of the developments described herein is mineral fixationof carbon dioxide by the manufacture of synthetic calcium carbonatecompositions as a component of a nano-composite SAS & FCA material.Thus, a novel process for producing precipitated calcium carbonate isdescribed herein, which enables the efficient use of “free” carbondioxide found in flue gas, and more particularly, which may use carbondioxide from flue gas containing relatively low concentrations of carbondioxide. Prior work, involving simply the production of precipitatedcalcium carbonate under pressurized conditions, was described in priorU.S. Pat. No. 6,125,356, entitled “High Speed Manufacturing Process forPrecipitated Calcium Carbonate employing Pressure Carbonation” wasissued Jun. 26, 2001, the disclosure of which is incorporated herein inits entirety by this reference. That process was capable of providing avariety of precipitated calcium carbonate (PCC) morphologies. Variousprecipitated calcium carbonates that can be manufactured by that processinclude distinct crystal morphologies, such as calcite scalenohedral aswell as calcite rhombohedral of various aspect ratios, and aragonite.SEM photographs of such crystals may be seen in FIGS. 21, 22, 23, and24. A PCC product manufactured under a pressure carbonation system maybe referred to herein as a Super Precipitated Calcium Carbonate(“S-PCC”).

The basic chemistry for producing precipitated calcium carbonatesincludes the steps of calcination, slaking, and carbonation. Thefollowing chemical reactions describe such steps:CaCO₃+ΔH→CaO+CO₂↑  (1) CalcinationCaO+H₂O→Ca(OH)₂+ΔH↑  (2) Slaking

-   -   ˜pH 12.4        Ca(OH)₂+CO₂        CaCO₃+H₂O+ΔH↑  (3) Carbonation    -   ˜pH 9.4

In order to produce the nano-composite product(s) described herein, anadditional step is required, as follows:CaSiO₃+CO₂→CaCO₃+SiO₂+ΔH↑  (4) Nano-Composite Cogeneration

The carbonation reaction (equation (3) above) is an equilibriumreaction. Therefore, as the soluble calcium ion is converted to calciumcarbonate (CaCO₃) precipitate, more dissolution of the calcium hydroxide(Ca(OH)₂) takes place from the slurry to increase the concentration ofthe calcium ion up to the solvent solubility limits (inverse temperaturedependent phenomenon), until all of the available calcium hydroxide isdissolved, and all available calcium ions have been converted intocalcium carbonate. When the process is further conducted to formnano-composite SAS & FCA material, as set forth in equation (4), it isof interest that carbon dioxide fixation using synthetic silicates underpressure is a novel method of carbon capture, i.e., fixation bymineralization.

Another aspect the developments described herein is the application ofsuch dual component nano-composites in paper (as in substitution forconventional pigments and fillers), and in paperboard coatings, and inother industrial applications such as fillers or pigments for paintsand/or coatings. As further described herein, the novel nano-structuredmaterials described herein have some unique properties. In anembodiment, such properties may make it useful as filler in papermakingoperations. In various embodiments, such use may provide some unusualand beneficial paper properties, or in unusual and beneficial papercoating properties, resulting in superior paper products when made withthe nano-structured materials described herein.

In various embodiments, the nano-structured composite materialsdescribed herein may be used at various degrees of substitution forcurrently used high performance coating pigments such as titaniumdioxide (TiO₂). In various embodiments, the nano-structured compositematerials described herein may be used at various degrees ofsubstitution for calcined and other naturally occurring clays. Theunique nano-composites described herein may also be used to enhance theperformance of various paper properties, such as to improve surfacestrength of coatings (pick strength), smoothness, appearance, shade,matte finish (lower sheet gloss), print quality, wet pick, and the like.In short, the nano-composite material described herein, including nanostructured amorphous silica and nano-fibrous crystalline aragonitecalcium carbonate, fits nearly all of the applicable criteria of anideal pigment.

In an embodiment, a unique nano-composite including synthetic fibrousstructured amorphous silica (SAS) and a nano fibrous crystallinearagonite precipitated calcium carbonate (FCA) is provided. In anembodiment, such nano-composite may be characterized by having highsurface area (approximately 40 to 200 meters squared per gram). In watersuspension, an embodiment of such unique nano-composite material mayhave a pH in the neutral pH range of 6.5 to 7.5. In an embodiment, suchnano-composite may have a very high water absorption, say in the rangeof from about 100% to about 300%. In an embodiment, such nano-compositemay have a high oil absorption, say in the range of from about 150% toabout 300%. The scanning electron microscope (SEM) photograph set forthin FIG. 2 clearly shows two distinct components. The first componentshown in the photograph is a globular, haystack, or pillow shapedstructure of approximately 10 microns to 40 microns in size. The firststructure includes “hair like” nano-fibers which in an embodiment may beapproximately 10 nm in diameter. In an embodiment, such fibers may beabout 3 microns to about 4 microns in length. Thus, in an embodiment,the aspect ratio of nano-fiber SAS & FCA may be approximately 100:1. Thesecond and prominent components in the SEM photograph provided in FIG. 2are the “needle” shaped fiber structures. In an embodiment, thoseprominent components have an estimated diameter of from about 100 nm toabout 200 nm, and length ranging from about 3 microns to about 10microns. Note that the X-Ray Diffraction (XRD) pattern analysis shown inFIG. 3 identified only a single crystalline component, which componentmatches the XRD pattern of calcium carbonate in the form of aragonite,with major peaks at 3.276, 3.398, and 1.977 D-spacing (in angstroms).Thus, the other structure was amorphous, rather than crystalline. Anenergy dispersive x-ray spectroscopy (“EDAX”) analysis (see FIG. 60)confirmed that the amorphous structure was silica. Thus, nano-compositeSAS & FCA which has been developed is a composite of structuredamorphous silica (SAS) and fibrous crystalline aragonite (FCA).

In an embodiment unique nano-composite materials may be produced by thepressure carbonation of one or more of selected synthetic crystallinecalcium silicate hydrates (CSH). Suitable synthetic crystalline calciumsilicate hydrates may include riversidite (see FIGS. 12 and 13), orfoshagite (see FIGS. 14 and 15), or tobermorite (see FIGS. 16 and 17),or xonotlite (see FIGS. 18, 19, and 20).

Several process steps may be utilized in the preparation of the uniquenano-composite materials described herein. In a very basic view, thereare two steps, as noted in the two blocks set forth in FIG. 25. In afirst step, one or more selected synthetic silicate hydrates areprepared by using hydrothermal reaction of calcareous materials, such aslime, with siliceous materials, such as quartz or diatomaceous earth(“DE”). In a second step, the just prepared one or more selected calciumsilicate hydrates are subjected to carbonation, under pressurizedconditions, to produce a nano-composite structure that includesamorphous silica, generally shaped in the form of the prior crystallinecalcium silicate hydrate, and additionally, crystalline calciumcarbonate, which in an embodiment, appears in the aragonite phase. In anembodiment, the process(es) may be carried out in pressurized reactors.

The manufacturing process of suitable nano-composite materials involvesreacting carbon dioxide reaction with synthetic calcium silicate hydrateunder pressure. In an embodiment the reaction of carbon dioxide underpressurized conditions provides carbonic acid in liquid solution forreaction with the one or more selected calcium silicate hydrates. In anembodiment, such the second step of formation of nano-composites, i.e.,pressurized carbonation may be carried out in the presence of one ormore seed materials, such as a selected amount of a previously preparednano-composite (e.g., a selected amount of aragonite). Further in anembodiment, reaction rates may be enhanced by utilization of acombination of selected amounts of calcium hydroxide and magnesiumhydroxide. In an embodiment, the process of pressurized carbonation, maybe carried out by controlling the starting pH to the range of from about10 to about 11.

The chemical reaction that occurs when synthetic calcium silicatehydrates are exposed to CO₂ is given in equation (4) above. In anexperimental nano-composite manufacturing process, the carbonation ofselected synthetic calcium silicate hydrates was carried out in apressurized reactor, using a pressure carbonation process. Theexperimental process variables included (a) initial reactor pressure,(b) initial reactor temperature, and (c) carbon dioxide flow rate to thereactor. In an embodiment, some process parameters and their ranges maybe considered as follows:

-   (1) Fibrous calcium silicate hydrate slurry solids (at about 36    grams per liter to about 120 grams per liter);-   (2) Carbon dioxide flow rates;-   (3) Time to reach reaction completion (in the range of from about 15    to 45 minutes);-   (4) Temperature profile ΔT (8° C.-20° C.);-   (5) Initial temperature—approximately 60° C.; and-   (6) Final temperature—approximately 70° C.

Production of Synthetic Calcium Silicate Hydrates

Set out below is a written description of a process for the productionof synthetic calcium silicate hydrates (CSH), used as precursormaterials for the production of novel nano-composite materials includingthe SAS & FCA composite described herein, and the manner and process ofmaking and using such calcium silicate hydrates, in full, clear,concise, and exact terms as to enable any person skilled in the art tomake and use the same, including the best mode presently contemplated bythe inventor for carrying out such process. However, for additionalreference, various additional embodiments for manufacturing andpreparation of various phases of synthetic calcium silicate hydrates aretaught in U.S. Pat. No. 6,726,807 B1, issued on Apr. 27, 2004, andentitled “Multi-Phase Calcium Silicate Hydrates, Methods for TheirPreparation, and Improved Paper and Pigment Products ProducedTherewith”, and in U.S. Pat. No. 7,048,900 B2, issued on May 23, 2006,and entitled “Method and Apparatus for Production of PrecipitatedCalcium Carbonate and Silicate Compounds in Common Process Equipment”.The reader is referred thereto for additional information, and thedisclosures of each of the just mentioned patents, including theirspecification, claims, and drawing figures, are incorporated herein intheir entirety by this reference in those states (countries) where suchincorporation by reference is permitted under applicable treaty,statute, or regulation.

Lime Slurry Preparation

Lime slurry is prepared according to generally accepted slakingprocesses. However, for purposes of further preparation of novelnano-composite SAS & FCA materials, an exception to commonly usedmethods may be advantageously utilized. For preparation ofnano-composite SAS & FCA compositions as described herein, the limeslurry need not be cooled. Instead, hot lime slurry (usually atapproximately 93° C.) may be screened and transferred directly to apressurizable reactor vessel. It should be noted that the solubility ofcalcium hydroxide is very low in water and is inversely proportional tothe temperature of that water. For example, the concentration of lime,as calcium oxide (CaO), in pure water at 0° C. is reported to be 0.14%.When the temperature of the water rises to the atmospheric boilingpoint, 100° C., the solubility of the lime, as calcium oxide (CaO),falls to 0.05%.

Siliceous Slurry Preparation

Various siliceous materials such as quartz, water glass, clay, puresilica, natural silica (sand), natural diatomaceous earth, fluxedcalcined diatomaceous earth, or combinations thereof, may be used assource(s) of siliceous material. In an experimental preparation ofcalcium silicate hydrates, an ultra-fine grade of fluxed calcineddiatomaceous earth (“FCDE”) was utilized, and was made into a waterslurry at approximately 146.2 grams FCDE per liter of slurry. Moregenerally, an aqueous slurry of siliceous material at a concentration offrom about 120 grams to about 180 grams of silica per liter of slurrycan be used. It should be noted that the solubility of silica/quartz,(unlike that of calcium hydroxide (Ca(OH)₂)), is directly proportionalto temperature. For example, quartz is only slightly soluble up to about100° C. From about 100° C. to about 130° C., quartz starts solubilizing,and around 270° C., a maximum solubility is reached at about 0.07%. Thedissolution of silica may be represented as per the reaction describedin equation (5):(SiO₂)n+2nH₂O→nSi(OH)₄  (5)

The solubility of silica in water may be increased by raising pH, suchas by using various additives (e.g., sodium hydroxide). Thesolubilization of silica is also at least to some extent a function ofparticle size, thus in an embodiment, a smaller particle size, such asmay be provided by use of ultra-fine fluxed calcined diatomaceous earth(FCDE) may be advantageous.

Hydro-Thermally Reacting the Lime Slurry and the Siliceous Slurry

First, the amount of CaO in a lime slurry and the amount of SiO₂ in adiatomaceous earth slurry may be adjusted to give a selected CaO/SiO₂mole ratio. Second, the concentration of the two slurries (CaO and SiO₂)and the final concentration of the mixture may be adjusted by usingwater so as to provide a selected final concentration, e.g., in anautoclave in experimental apparatus, of between about 24 and about 120grams/liter.

In an embodiment, a reaction was carried out in a pressurized reactorvessel, with three major steps:

-   (1) Heating the slurry to a selected temperature (e.g., in the range    of from about 180° C. to about 250° C.).-   (2) Reacting at the selected temperature for a specified time (e.g.,    in the range of from about 120 minutes to about 240 minutes).-   (3) Stopping the reaction and cooling down the resultant mixture of    water, calcium silicate hydrates, and residual reactants, during a    suitable period of time (e.g., from about 25 minutes to about 30    minutes, or perhaps longer), which time may vary according to the    cooling/quenching apparatus available or selected in a particular    process configuration.

In an experimental embodiment, a pressurized reactor vessel was cooleddown by passing quenching water through an internal cooling coil andexternal jacketed cooling system. The cool down process took from about30 minutes to about 60 minutes, in order to reduce the temperature from230° C. to 80° C. Generally, the inverse solubility of lime in waterwith respect to temperature has been recognized, and thus utilized in aneffort to produce the desired composition and phases of calcium silicatehydrate material.

Without limiting the developments described herein to any particularmechanism or theory, in some respects, it is presently believed thatcertain reactions occur during the hydrothermal reaction betweencalcious material and siliceous material. More particularly, solidcalcium hydroxide Ca(OH)₂ particles may react with SiO₂ in a gel phaseto yield a calcium silicate hydroxide whose crystallochemical structurecan be written as Ca₆Si₆O₁₇(OH)₂ (xonotlite). As the temperature isfurther raised from about 180° C. to about 250° C., calcium silicatehydrate condenses with the remaining Ca(OH)₂ particles to give yetanother calcium silicate hydrate, this time with a distinct X-raydiffraction pattern and a crystallochemical formula of Ca₄(SiO₃)₃(OH)₂(foshagite). Thus, the process(es) described herein may produce not onlysingle phase calcium silicate hydrates, but may also produce calciumsilicate hydrates having multiple phases therein. Different calciumsilicate hydrates may be made by changing the lime/silica ratio, slurryconcentration, reaction temperature and reaction time. The use ofdifferent additives like sodium hydroxide, sugar, and chelatingcompounds may also be utilized and manipulated to create diverseproducts. More generally, a variety of calcium silicatehydrates—including xonotlite, tobermorite, riversidite, andfoshagite—may be prepared by manipulating the following processparameters:

-   (1) Lime/Silica ratio;-   (2) Reaction Temperature;-   (3) Slurry Concentration;-   (4) Reaction Time;-   (5) Heating and Cooling Sequence.

Various phases of calcium silicate hydrates were produced by changingthe calcium to silica molar ratio (e.g., from 0.75 to 1.35), by changingthe reactant concentrations (e.g., from 48 to 120 grams per liter, andby changing the reaction temperature (e.g., from 180° C. to 260° C.),and by changing the reaction time (e.g., in the range of from about 2hours to about 4 hours). Generally, for further production ofnano-composite SAS & FCA products, the CSH products from a selected setof reaction conditions may be cooled from a maximum of 260° C. to aminimum of between about 180° C. and 70° C.

High Pressure Reactor & Equipment for Manufacturing Multiple CalciumSilicate Hydrates, Lab Scale

In an embodiment, the process described herein utilizes a hydrothermalreaction that may be carried out under super-atmospheric conditions,using pressurized reactor equipment. As an example, a reactor used inthe lab was a specialized, high pressure, high temperature, two literreactor vessel. It was fitted with an outside jacketed heater andinternal cooling coil system. The reactor was also fitted with animpeller to provide mixing in the reactor (e.g., Rustin 200 impeller).In a laboratory reactor embodiment, the agitator/impeller was connectedto a variable speed magnetic drive motor. Additionally, the reactor wasfitted with a sample/dip tube, and with a vent system, which was used tomaintain pressure at a desired level. The completely assembled reactorwas capable of pressures of up to 68.95 bar. All heating and coolingprocesses of the reactor were controlled via an external controller.

In an embodiment, the process included reacting lime at approximately240 grams/liter with a silica source (e.g., diatomaceous earth and/orquartz) at about 180 grams/liter. The reactions were made in apressurized reactor over temperature range of 180° C. to 250° C. and thecorresponding steam pressure, ranging from 13.8 bar to 41.37 bar. Thetotal reaction time was approximately 4 to 6 hours. The resulting slurryconcentration ranged from 36 grams per liter to 120 grams per liter.

The process conditions for the hydrothermal reaction such as calcium tosilica ratio, slurry solids percentage, and temperature of reaction,were varied as shown in Table 1 below to prepare different crystalphases of calcium silicate hydrates, such as riversidite, tobermorite,xonotlite, and foshagite. For further specific examples, see U.S. Pat.No. 6,726,807 B1, issued on Apr. 27, 2004 for “Multi-phase CalciumSilicate Hydrates, Methods for Their Preparation, and Improved Paper andPigment Products Produced Therewith”, as noted herein above.

TABLE 1 Synthetic Calcium Silicate Hydrate Preparation - ProcessConditions Reaction Conditions Products Calcium/ Slurry SolidsTemperature Crystal Crysto-Chemical Silica Ratio (grams/liter) (° C.)Phase Formula 0.76 120 188 Riversideite Ca₅Si₆O₁₇(OH)₂ 0.90 72 200Tobermorite Ca₅Si₆O₁₆(OH)₂ 1.05 54 230 Xonotite Ca₆Si₆O₁₇(OH)₂ 1.30 48250-300 Foshagite Ca₅Si₆O₁₇(OH)₂

Some of the characteristics of the above noted phases of crystallinecalcium silicate hydrates (CSH) are provided in Table 2. Such crystalphases may be characterized, at least in part, by their: (1) X-Raydiffraction pattern, (2) surface area, (3) water absorption, (4) aspectratio, and (5) bulk density. A graphical representation of typicalsurface areas of the noted phases of calcium silicate hydrates isprovided in FIG. 8. A graphical comparison of the surface area ofcalcium silicate hydrates (CSH) with titanium dioxide (TiO₂) and withprecipitated calcium carbonate (PCC) is shown in FIG. 9. A graphicalcomparison of the aspect ratio of calcium silicate hydrates (SCH) withtitanium dioxide (TiO₂) and with precipitated calcium carbonate (PCC) isshown in FIG. 10. A graphical comparison of the bulk density of calciumsilicate hydrates (CSH) and titanium dioxide (TiO₂), pulp fibers, andcalcium carbonate is shown in FIG. 11.

TABLE 2 Characteristics of Various Calcium Silicate Hydrate PhasesCrystal Phase Riversideite Tobermorite Xonotlite Foshagite I. X-rayDiffraction Peaks (Å) 1. Major Peak 3.055 11.0 3.02 2.93 2. Minor Peeks3.58, 2.80 3.71, 3.00 2.04, 8.50 2.16, 4.96 II. Surface Area 275-325175-250  80-150 20-50  (m²/g) III. Water Absorption 200-350 400-550600-750 800-1000 (%) IV. Aspect Ratio ~5:1 ~7.5:1 ~30:1 ~200:1 (L:D) V.Brightness (ISO) 90-94 92-94 94-96 94-96  VI. Bulk Density 0.2 0.2 0.20.2 (g/cc)

The scanning electron microscope (“SEM”) photographic images andcorresponding x-ray diffraction (“XRD”) patterns of the above noted fourdifferent phases of calcium silicate hydrate (CSH) products are shown inFIGS. 12 through 19. The reaction conditions clearly influence thecrystal structure and habit, as well as the chemical composition andsome physical properties, including surface area, water absorption,aspect ratio, brightness and bulk density. Depending on reactionconditions, such calcium silicate hydrates (CSH) may be produced asmacro particles, or as nano-fibers, or as macro fibers with a broadrange of surface area, particle sizes, shapes and aspect ratios, as canbe seen in the above referenced drawing figures, and as indicated in theabove Tables 1 and 2. Additional SEM photographs provided in FIG. 20illustrates an embodiment that provides an example of a structure—in theform of a haystack or pillow, fur ball, or similar structure—that issuitable as a calcium silicate hydrate (CSH) that may be useful as astarting material, i.e. a precursor for replacement of material thereinwith amorphous silica, in the manufacture of a nano-composite (SAS &FCA) containing structured amorphous silica and fibrous calciumcarbonate crystals in the form of aragonite.

A specific example of the experimental preparation of a selectedsynthetic nano fibrous calcium silicate hydrate, namely xonotlite, isnow provided. The reaction was carried out at selected conditions, inorder to produce xonotlite. The reaction was carried out in a highpressure reactor having a volume of 7.5 liters, available from ParrInstrument Company. The hydrothermal process conditions are given inTable 3 below. The resulting xonotlite properties are summarized inTable 4.

TABLE 3 Process Conditions for manufacture of Synthetic Xonotlite Ca/SiRatio 1.05 Solids (g/L) 54 Temperature (° C.) 230 Reaction Time (hrs) 2Reaction Volume (L) 4.8 Total Mass (g) 260

TABLE 4 Properties of Synthetic Xonotlite pH 11.6 Surface Area (m²/g)137 Water Absorption (%) 315 Oil Absorption (%) 379 X-Ray DiffractionXonotlite (See FIG. 5) Scanning Electron See FIG. 4 Microscope TotalMass (g) 260

The xonotlite slurry had a pH of 11.6. The surface area (BETmeasurement) for the dry xonotlite was 137 square meters per gram. Thewater and oil absorption of the dry xonotlite were 315% and 379%respectively. The scanning electron microscope (SEM) photograph andX-ray diffraction (XRD) pattern of the manufactured xonotlite are shownin FIGS. 4 and 5 respectively. The X-ray diffraction pattern set forthin FIG. 5 shows the predominate presence xonotlite. In FIG. 4, the SEMphotograph shows, in the circled area, a secondary structure, having ahaystack or pillow configuration, that provides a fibrous hollowmacrosphere structure made up primarily of nano-fibers with layershaving interstitial spaces and wherein inner fibers are seen throughouter layers of fibers.

Formation of Nano-Structured Composite.

Cogeneration of a nano-composite including structured amorphous silica(SAS) and fibrous crystalline aragonite carbonate (FCA) by pressurecarbonation may be accomplished, once one or more selected calciumsilicate hydrates are available as a raw material, and a supply ofcarbon dioxide is available. The manufacture of a nano-composite (SAS &FCA) material involves pressure carbonation. In an embodiment, themanufacture of a nano-composite (SAS & FCA) material may be done in acogeneration fashion, that is, the reaction with the xonotlite substrateto replace the same with amorphous silica is carried out at the sametime and under the same reaction conditions while fibrous crystallinearagonite is manufactured on, in, or protruding from the substrate CSHstarting material, here the xonotlite substrate.

Seeding.

It has been found that efficiency of the carbonation of fibrous calciumsilicate hydrate may be significantly improved by adding certain seedmaterials, and/or reaction promoter materials, and/or catalysts, and/orpH modifiers, as further described below. In an embodiment, a suitableseed material may include previously generated nano-composite (SAS &FCA) material. In an embodiment, a suitable seed material may includeone or more additional calcium silicate hydrate precursors. Additionalseed materials may include commercially produced calcium carbonates(CaCO₃) in the aragonite phase. The total quantity of seed materials tobe added may range from about 2% to about 20% of the total weight ofreactants.

Catalysts/Promoters

Catalysts may include a mixture of calcium hydroxide (Ca(OH)₂) andmagnesium hydroxide (Mg(OH)₂). The total quantity of catalytic materialmay range from about 2.0% to about 10.0% of the total weight ofreactants. The ratio of calcium hydroxide to magnesium hydroxide mayrange from about 1:1 to about 2:1. Such catalysts also serve as pHbuffers and promoters, and may also help to remove certain impuritiesfrom process water. In an embodiment, before the start of pressurecarbonation, the described seed materials, and catalysis/promoters wereadded to a xonotlite slurry produced as described above.

Pressure Carbonation of Synthetic Calcium Silicate Hydrates (CSH)

In an experimental embodiment, as seed material was added to a hotsilicate slurry (<70° C.), the slurry was cooled to a final temperatureranging from 50° C. to 75° C. The reactor vessel was then pressurizedusing a non-reactive gas to a pressure ranging from 2.0 to 6.9 bar.After that, a gas flow containing carbon dioxide (CO₂) was injectedunder pressure into the reactor vessel. The carbon dioxide compositionof the gas stream varied between about 5% and to about 100% CO₂ byweight. The total gas flow was between 1.3 liters per minute to 7.2liters per minute, and provided a theoretical reaction rate of betweenabout 1.5 grams per liter per minute to about 8 grams per liter perminute. In laboratory experimental reactor apparatus, throughout thecarbonation reaction the reactants were agitated with a built-inagitator. The paraxial tip speed of the agitator was 223.5 meters perminute (at a rotational speed of 700 RPM). In the laboratory, thereaction was carried out in a 5.7 liter volume pressurized stirredreactor manufactured by Parr Instrument Company, Moline, Ill., USA (seehttp://www.parrinst.com). Rotational speed (RPM) was measured by atachometer attached to the motor of the agitator. The reactiontemperature was measured by using a thermocouple temperature probe.Carbon dioxide flow rate was measured using a carbon dioxide specificflow meter with a totalizer to calculate the total carbon dioxideconsumed. The pressure was recorded by a pressure probe and shown on apressure gauge. The carbonation reaction between the silicate slurry andcarbon dioxide is an exothermic reaction. Thus, as the reactionproceeded, the temperature of the slurry increased. The end of thecarbonation reaction was indicated by the reactor temperature reaching apeak and then stabilizing to a plateau. Usually the increase intemperature (ΔT) was in the range of 5° C. to 15° C., depending on thereactivity of the silicate, and the composition of the starting calciumsilicate hydrate. The end of the carbonation reaction was also indicatedby plotting the temperature profile.

During reaction, the incoming carbon dioxide (CO₂) was continuouslyconsumed by the calcium constituents of the calcium silicate hydrate(CSH). Thus, while the CO₂ was initially introduced at a pressure ofapproximately 70 psig, and, while the temperature increased due to theexothermic nature of the carbonation reaction, the pressure in thereactor remained fairly close to the initial pressure. However, at theend of the reaction, the calcium ions (Ca⁺²) and carbonate ions (CO₃ ⁻²)were fully consumed. In the experimental apparatus, the excess carbondioxide at the end of the reaction started to increase the pressure ofthe reactor. Thus, while the end of the reaction was indicated by a plotof temperature versus time; another indicator was an increase in therate of change in the pressure in the reaction vessel versus time.

Thus the completion of the carbonation of calcium silicate hydrates wasindicated by the temperature reaching a plateau and by the pressureincreasing significantly. The progress of the pressure carbonationreaction was also monitored by following the pH and conductivity of theslurry. The pH, as per equation 2 above decreased from an initial pH ofapproximately 11 to a final pH between about 6.5 and about 7.5. Theconductivity also fell as the free calcium (Ca⁺²) ions were used up toproduce non-ionic CaCO₃. The just noted pH was measured after thetemperature reached a maximum and the rate of change of pressure startedto increase.

One test utilized to establish the nature of products actuallymanufactured was the Mohr's Salt test. That test involved applying asolution of ammonium iron(II) sulfate (Mohr's Salt, namely(NH₄)₂Fe(SO₄)₂.6H₂O)) to a sample of the nano-composite slurry. Thedevelopment of a green color indicated the presence of aragonite crystalphase. This test was further confirmed by an X-ray diffraction (XRD)analysis. Another test conducted was the surface area of the finalproduct, using the BET method. In an embodiment, a range of surfaceareas was found, from about 50 square meters per gram to about 150square meters per gram.

An example of cogeneration of a nano-composite (SAS & FCA), namelystructured amorphous silica and fibrous crystalline aragonite carbonate,is now provided in further detail. A reaction was carried out accordingto the conditions necessary to produce a nano-composite of structuredamorphous silica and fibrous crystalline aragonite carbonate. Thereaction was carried out in a high pressure 7.5 L reactor manufacturedby Parr Instrument Company. The pressure carbonation process conditionsare given in Table 5 below. The resulting nano-composite (SAS & FCA)material properties are summarized in Table 6. Previous work has shownthat different sources of silica (Flux calcined diatomaceous earth,ground quartz, and regular diatomaceous earth) will result in differentsilicate properties. The xonotlite formation reaction example above wasconducted using a flux calcined Diatomaceous Earth product as a silicasource. The X-Ray Diffraction pattern and SEM photograph of a resultingnano-composite (SAS & FCA) material are provided in FIGS. 6 and 7,respectively.

TABLE 5 Summary of Process Conditions-Carbonation of Xonotlite InitialTemp (° C.) 60 Final Temp (° C.) 70 ΔT (° C.) 10 Volume (L) 4.8 Solids(g/L) 54 Total Mass (g) 260 CO₂ Flow (L/min) 3.6 Start Pressure (bar)4.8

Product Testing Parameters

Some product parameters tested were:

-   (1) Surface Area—BET Method (m²/gram);-   (2) pH;-   (3) Chemical Test for crystal structure (Aragonite or Calcite) (e.g.    Mohr's Salt test);-   (4) Water Absorption;-   (5) Oil Absorption;-   (6) X-Ray Diffraction Pattern (XRD; see FIG. 7); and-   (7) Scanning Electron Micrograph (SEM; see FIG. 6).

Some calculated parameters were:

-   (1) CO₂ Efficiency (%); and-   (2) Reaction Rate (grams per liter per minute).

TABLE 6 Summary of Properties of Nano-Composite including Nano FibrousStructured Amorphous Silica (SAS) & Nano Fibrous Crystalline AragoniteCalcium Carbonate (FCA) pH 6.7 Surface Area (m²/g) 119 Water Absorption(%) 277 Oil Absorption (%) 230 X-Ray Diffraction Aragonite (See FIG. 7)Scanning Electron See FIG. 6 Microscope Solids (g/L) 75.5 ReactionVolume (L) 4.8 Total Mass (g) 354 CO₂ Used (L) 65 CO₂ Efficiency (%) 76%

As shown in FIG. 7, the XRD pattern for nano-composite (SAS & FCA)material showed that aragonite was predominantly present, as well as atrace of tobermorite. Thus, the nano-composite (SAS & FCA) includes bothfibrous amorphous silica and fibrous crystalline aragonite. In FIG. 6,the photographs taken with a scanning electron microscope show twodistinct structures in the nano-composite SAS & FCA. A first structureresembles the shape of one of the raw materials, namely the xonotlitecalcium silicate hydrate. The second structure resembles crystallinearagonite precipitated calcium carbonate. However, since crystallinesilica was virtually absent in the X-Ray diffraction pattern, it may beinferred that the silica component was, after the carbonation reaction,essentially in a non-crystalline, i.e. amorphous form. The SEMphotograph of the raw materials, namely synthetic xonotlite and itscorresponding XRD are given in FIGS. 4 and 5. The SEM photograph of theresulting nano-composite material (SAS & FCA) compound, after thepressure carbonation process, as well as its corresponding XRD, areshown in FIGS. 6 and 7, respectively.

A comparison of a selected raw material, and of a sample of the finishedproduct, namely a nano-composite (SAS & FCA) may be instructive. An SEMphotograph of a selected raw material, namely xonotlite crystals, isshown in FIG. 4. The XRD for those xonotlite crystals is provided inFIG. 5. As illustrated in FIG. 5, after carbonation of the xonotlite rawmaterials, the SEM of the carbonated xonotlite showed two distinctstructures, namely aragonite (dashed oval) and SiO₂ (solid circle).However, as shown in FIG. 7, the X-Ray diffraction pattern of the novelnano-composite materials (SAS & FCA) showed the presence of a singlepredominant crystalline component, namely aragonite calcium carbonate.Thus, it can be inferred that the remaining SiO₂ was in an amorphousform. Thus, it has been determined that the carbonation of syntheticcalcium silicate hydrates is technically feasible, and the workdescribed herein has resulted in a novel, unique nano-composite (SAS &FCA) product.

In one aspect, the pressure carbonation of synthetic calcium silicatehydrates resulted in the unexpected formation of a nano-fibrouscrystalline aragonite calcium carbonate (FCA). Such crystal structurewas also confirmed by the chemical chromatic test using Mohr's Salt(green color). And, since the xonotlite, i.e., the silica portion of theXRD shown in FIG. 5 was not detected in the XRD pattern of thenano-composite illustrated in the XRD shown in FIG. 7, it is postulatedthat the final, carbonated nano-composite (SAS & FCA) material wasmostly nano-fibrous structured amorphous silica (SAS), which wasproduced from the crystalline calcium silicate hydrate xonotlite.

Example 1—Novel Nano-Composite (SAS & FCA) Production

Step 1: Preparation of Synthetic Calcium Silicate Hydrate—Xonotlite

Initially, 117.4 grams of W rotary pebble lime (from Graymont Lime Co.)was accurately weighed and slaked in 350 milliliters of high puritywater prepared by reverse osmosis treatment. The slaking reaction isexothermic and caused the slurry temperature to rise to near boiling.When the slurry temperature was very near boiling, and before much ofthe water had evaporated, an additional 90 milliliters of water wasadded to both dilute and cool the slurry. The slurry was then agitatedfor 30 minutes to insure slaking completion. Then, the slurry wasscreened through a 100 mesh screen. The slurry was then transferred to a5 liter autoclave, and tested for lime availability in accordance withASTM method C25, entitled “Standard Test Methods for Chemical Analysisof Limestone, Quicklime, and Hydrated Lime.” Approximately 137.2 gramsof fine fluxed calcined diatomaceous earth (FCDE), from Eagle PicherMinerals, Reno, Nev. (namely Celatom brand product designation MW-27)was weighed and added to 750 ml of hot water (concentration ofapproximately 182 grams/liter). The silica slurry was added to thescreened and tested lime slurry. The exact amount of silica slurry addedto lime slurry was determined by the lime availability such that aCaO/SiO₂ mol ratio of approximately 1.05 would be maintained. The totalslurry volume was also adjusted by adding water to a final concentrationof 54 grams per liter. The autoclave was continuously agitated at aconstant speed of 250 rpm. The starting temperature of the slurry wasapproximately 25° C. The reactor was heated for approximately 100minutes in order to reach the target temperature of 230° C. Thetemperature was maintained at 230° C. for 2 hours, after which,“quenching” water was flushed through the cooling coil built inside thereactor. The cooling process was maintained until the temperature in thereactor reached approximately 80° C. (roughly 30 minutes), at whichpoint the reactor was depressurized and opened. Then, the reactionproducts were transferred to a holding vessel for storage. One portionof the resultant slurry was tested for pH. Another portion of theresultant slurry was dried in an oven at 105° C. for 12 hours. Duringthe drying process, the slurry formed hard lumps, which had to be brokenup through the use of a mortar and pestle. The powdered, dry product wasbrushed through a 100 mesh screen to insure product uniformity duringtesting. The pigment in this example was designated sample batch #MW-2.

Tests carried out on the dry powder were as follows:

-   (1) Surface Area (BET Method);-   (2) pH;-   (3) Percent Water Absorption;-   (4) Percent Oil Absorption;-   (5) X-ray diffraction analysis; and-   (6) Scanning Electron Micrograph (SEM).

The process conditions for xonotlite formation are given in Table 7below. The pigment properties of xonotlite are given in Table 8 below.

TABLE 7 Process Conditions of Xonotlite Formation (MW-2) Molar Concen-Tempera- Reaction Raw Ratio tration ture Time Batch # Material(CaO/SiO₂) (g/L) (° C.) (hours) MW-2 FCDE 1.05 54 230 2

TABLE 8 Properties of Xonotlite (MW-2) Water Oil Batch # BET (m²/g) pHAbsorption (%) Absorption (%) MW-2 137 11.6 315 379

The x-ray diffraction pattern of this synthetic multiphase calciumsilicate hydrate, namely xonotlite, is given in FIG. 5. This productgave a unique x-ray pattern. The pattern indicated that the powder hadone major phase. The summary of the characteristic “peaks” is shown inTable 9. The major peaks for phase I were found to indicate the presenceof calcium silicate hydrate—xonotlite—Ca₆Si₆O₁₇(OH)₂) with major peaksat d(Å)=3.107, d(Å)=1.75 and a minor peak at d(Å)=3.66.

TABLE 9 X-ray diffraction peak analysis and summary for product labeledbatch # MW-2 in Table 8 above. Common Crystallchemical d-spacingd-spacing d-spacing Name Formula (Major) (median) (Minor) XonotliteCa₆Si₆O₁₇(OH)₂ d = d = d = 3.107 Å 1.75 Å 3.66 Å

Some SEM pictures at 1500 times magnification are shown in FIG. 4. TheSEM clearly shows the “fibrous” structure of xonotlite. The diameter ofthe “nano-fibers” ranges from about 10 nm to about 20 nm while thelength ranges from about 1 microns to about 5 microns. Such dimensionsresult in a material having an aspect ratio of about 100:1. The SEM alsodepicts the three dimensional structure of the secondary particles ofcalcium silicate hydrates. Such secondary structure has a “pillow” or“haystack” or “globular” type appearance. The structure appears to havebeen formed by an interlocking of the primary “fibrous” crystals andsome inter-fiber bonding due to hydro gel of silica formed during theinitial stages of hydro-thermal reaction. Because of these two mainreasons, the secondary particles are fairly stable and do notsignificantly lose their 3-d structure when subjected to process shear.In addition, these particles also seem to withstand the pressureencountered during the calendaring or finishing operations integral topapermaking and coating. The median size of the secondary particles, asseen, ranges from about 10 microns to about 40 microns.

Step 2: Cogeneration of Nano-Composite (SAS & FCA) Having a StructuredAmorphous Silica Component and a Fibrous Crystalline Calcium Carbonate(Aragonite) Component, by Pressure Carbonation.

The xonotlite slurry produced in step 1 was placed into a reactor at aslurry concentration of 0.45 pounds per liter. The starting carbonationtemperature was 60° C. The reaction was carried out under a startingpressure of 70 psig. Carbon dioxide gas was bubbled through the reactor.The flow of carbon dioxide was at the rate of 3.6 liters per minute. Asthe reaction proceeded, the reaction temperature increased, with thetemperature starting at 60° C. and ending at approximately 70° C. Theend of the reaction was indicated when the temperature reached a maximumand then declined. The point of inflection in the temperature curve wastaken as the completion point of the carbonation reaction. The pressurein the vessel spiked due to the incoming but unreacted CO₂. The reactorwas first depressurized. Then, the reactor was opened and the reactionproducts were transferred to a holding vessel for storage. A portion ofthe resultant slurry was dried in an oven at 105° C. for 12 hours.During the drying process, the slurry formed hard lumps, which had to bebroken up through the use of a mortar and pestle. The now powdered, dryproduct was brushed through a 100 mesh screen to insure productuniformity when testing. The pigment in this example was designatedbatch #MW-2-ARA.

Test were carried out on the dry powder were as follows:

-   (1) Surface Area (BET Method);-   (2) pH;-   (3) Percent Water Absorption;-   (4) Percent Oil Absorption (ASTM D281-12);-   (5) Mohr Salt Test;-   (6) X-ray diffraction analysis; and-   (7) Scanning Electron Micrograph (SEM).

The process conditions for cogeneration of nano-composites designated asbatch #MW-2-ARA are given in Table 10. The product properties for thenano-composites designated as batch #MW-2-ARA are given in Table 11.

TABLE 10 Process conditions of MW-2-ARA Start Final Start CO₂ FlowTemperature Temperature Δ T Pressure Rate Batch # (° C.) (° C.) (° C.)(bar) (L/min) MW-2- 60 70 10 4.8 3.6 ARA

TABLE 11 Properties of Nano-Composite (MW-2-ARA) Water Oil BETAbsorption Absorption Mohr Salt Batch # (m²/g) pH (%) (%) Test MW-2-ARA119 6.7 277 230 Green

The XRD pattern given in FIG. 7 for an embodiment of the nano-compositeSAS & FCA material clearly identifies the presence of crystallinearagonite as a predominant component of the material. However, no XRDpeak for a crystalline silica composition (SiO₂) was observed.

As also seen in FIG. 7, the XRD pattern for a nano-composite (SAS & FCA)material showed a peak for precipitated calcium carbonate, namelyaragonite (fibrous crystalline aragonite), and a peak for a trace ofsynthetic calcium silicate hydrate (namely tobermorite). As seen in FIG.6, however, the SEM photographs for the nano-composite (SAS & FCA) showstwo distinct structural features, namely SiO₂ (in the solid circle) andaragonite (in the dashed oval). The first structural feature, SiO₂,resembles the original starting material, namely a haystack, pillow, orglobular structure similar to the structure seen in the xonotlite (seethe large circle illustrated in FIG. 4 above). The second structuralfeature resembles a crystalline aragonite calcium carbonate (see FIG.21). The presence of a silica product was confirmed by an EDAX analysis(see FIG. 60). Since the silica product was virtually absent in theX-Ray diffraction (XRD) pattern of the nano-composite (SAS & FCA) asshown in FIG. 7, it may be inferred that the silica component wasessentially non-crystalline, or amorphous.

Thus, as generally described above, it can be appreciated that a novelcomposition of matter has been created, in the nature of anano-composite (SAS & FCA) including a fibrous amorphous silicacomponent and a crystalline calcium carbonate component. In anembodiment, the fibrous amorphous silica component may be provided inthree-dimensional haystack (which may alternately be said to be a pillowshaped or globular shape three-dimensional structure). In an embodiment,the fibrous amorphous silica component presents a fibrous structurehaving interstitial spaces between the amorphous silica fibers, withinner layers and outer layers of amorphous silica fibers, and havingirregular interlacing amorphous silica fibers or filaments which arefixed in relation to each other. The crystalline calcium carbonatecomponent includes aragonite needle structures, which may be grown from,that is, attached to and arising outward from, a portion of the fibrousamorphous silica component. In various embodiments, the nano-composite(SAS& FCA) structure has a major axis of length L (e.g., L would be thediameter D if the structure were truly spherical, or L would be themajor axis of an ovoid, i.e. an elliptically shaped solid, rathersimilar to irregular solids shown SEM photographs in the various drawingfigures) in the range of from about 10 microns to about 40 microns. Invarious embodiments, such novel nano-composites may have a surface areaof from about 40 meters squared per gram to about 200 meters squared pergram. In various embodiments, such novel nano-composites may have asurface area in the range of from about 50 meters squared per gram toabout 150 meters squared per gram. In various embodiments, the amorphoussilica fibers may have a length of from about 3 microns to about 4microns. In various embodiments the amorphous silica fibers may have adiameter of about 10 nm. In various embodiments, the amorphous silicafibers may have an aspect ratio of from about 50:1 to about 100:1. Invarious embodiments, the aragonite needle structures comprise aragonitecrystals which may have a length of from about 1 micron to about 10microns. In various embodiments, the aragonite crystals may have alength of from about 3 microns to about 5 microns. In variousembodiments, the aragonite needle structure may comprise aragonitecrystals having a diameter of from about 100 nm to about 200 nm. Invarious embodiments, the aragonite crystals may have an aspect ratio offrom about 50:1 to about 100:1. In various embodiments, the novelnano-composite composition of matter as set forth herein may be furthercharacterized in that in an X-ray diffraction of the nano-compositecomposition, a major peak for aragonite appears at approximately 3.22angstroms. In various embodiments, the novel nano-composite compositionof matter described herein may be further characterized in that whenmixed with water, the pH is in the range of from about 6.5 to about 7.5.

In various embodiments, nano-composites (SAS & FCA) materials asdescribed herein may have a composition such that their water absorptioncharacteristic is in the range of from about 100% to about 300%. Invarious embodiments, nano-composites (SAS & FCA) materials as describedherein may have a composition such that their water absorptioncharacteristic is at least 100%. In various embodiments, nano-composites(SAS & FCA) materials as described herein may have a composition suchthat their oil absorption characteristic id in the range of from about150% to about 300%. In various embodiments, nano-composites (SAS & FCA)materials as described herein may have a composition such that their oilabsorption characteristic is in the range of from about 200% to about250%.

Example 2—Novel Nano-Composite (SAS & FCA) Production

Step 1: Preparation of Synthetic Calcium Silicate Hydrate—Xonotlite

A multiphase calcium silicate hydrate of was formed by way of thehydrothermal reaction of lime and silica as described in Example 1. Thedifference from Example 1 was that the silica source used in thisExample 2 was a non-calcined or natural diatomaceous earth. The samplewas labeled as batch #MN-2. The process conditions for preparation ofsample identified as batch #MN-2 are given in Table 12. The pigmentproperties for the sample identified as batch #MN-2 are given in Table13.

TABLE 12 Process conditions of Xonotlite Formation (MN-2) Molar ReactionRaw Ratio Concentration Temperature Time Batch # Material (CaO/SiO₂)(g/L) (° C.) (hours) MN-2 Natural 1.05 54 230 2 DE

TABLE 13 Properties of Xonotlite (MN-2) Water Oil Absorption Batch # BET(m²/g) pH Absorption (%) (%) MN-2 75 12.2 432 290

The graph of the XRD pattern of this sample of crystalline xonotlite isgiven in FIG. 27. The SEM photograph of this sample of crystallinexonotlite is given in FIG. 26.

Step 2: Cogeneration of Nano-Composite (SAS & FCA) Having a StructuredAmorphous Silica Component and a Fibrous Crystalline Calcium Carbonate(Aragonite) Component, by Pressure Carbonation.

In this step, the same process conditions were followed as in Example 1.The resulting sample was labeled as batch #MN-2-ARA. The processconditions for the cogeneration reaction are given in Table 14. Thepigment properties of the resultant novel nano-composite (SAS & FCA)material are given in Table 15:

TABLE 14 Process conditions of Batch # MN-2-ARA Start Final Start CO₂Flow Temperature Temperature Pressure Rate Batch # (° C.) (° C.) Δ T (°C.) (bar) (L/min) MN-2- 60 70 10 4.8 3.6 ARA

TABLE 15 Properties of Nano-Composite Batch # MN-2-ARA Water Oil BETAbsorption Absorption Mohr Salt Batch # (m²/g) pH (%) (%) Test MN-2-ARA119 6.7 277 230 Green

The graph of the XRD pattern of a nano-composite SAS & FCA material isprovided in FIG. 3. The SEM photograph of such nano-composite SAS & FCAis given in FIG. 2.

Example 3—Novel Nano-Composite (SAS & FCA) Production

Step 1: Preparation of Synthetic Calcium Silicate Hydrate—Tobermorite

A multiphase calcium silicate hydrate of was formed by hydrothermalreaction of lime and silica as generally described in Example 1. Thedifferences were that the silica source in this Example 3 was courseground quartz (Sil-Co-Sil 106 from US Silica). The reaction temperaturewas reduced to 220° C., and the reaction time was increased to 4 hours.Finally, the CaO/SiO₂ molar ratio was increased to 1.30 while the solidscomposition of the slurry was decreased to 43 grams per liter. Thiscalcium silica hydrate (CSH) was made in a 30 gallon reactor withsimilar temperature probes and an agitator similar to the reactorsdescribed above. The sample was labeled as batch #T30-8-078. The processconditions for preparation of sample as batch #T30-8-078 are given inTable 16. The pigment properties are for sample batch #T30-8-078 givenin Table 17:

TABLE 16 Process conditions of Tobermorite Formation (T30-8-078) Con-Reaction Raw Molar Ratio centration Temperature Time Batch # Material(CaO/SiO₂) (g/L) (° C.) (hours) T30-8- Ground 1.30 43 220 4 078 Quartz

TABLE 17 Properties of Tobermorite (T30-8-078) Water Oil AbsorptionBatch # BET (m²/g) pH Absorption (%) (%) T30-8-078 239 10.8 559 600

The SEM photograph of this calcium silicate hydrate is shown in FIG. 16.The graph of the XRD pattern of this calcium silicate hydrate isprovided in FIG. 17.

Step 2: Cogeneration of Nano-Composite (SAS & FCA) Having a StructuredAmorphous Silica Component and a Fibrous Crystalline CarbonateComponent, by Pressure Carbonation.

In this example, seed material was added to the slurry. Otherwise, theprocess conditions were generally the same as set forth in Example 1.The sample ID was batch #T30-8-078-ARA. The process conditions forcogeneration of sample batch #T30-8-078-ARA are given in Table 18. Thepigment properties for sample batch #T30-8-078-ARA are given in Table19:

TABLE 18 Process conditions for preparation of T30-8-078-ARA Start FinalStart Temperature Temperature ΔT Pressure CO₂ Flow Rate Batch # (° C.)(° C.) (° C.) (bar) (L/min) T30-8- 60 70 10 4.8 112 078-ARA

TABLE 19 Properties of Nano-Composite (T30-8-078-ARA) Water Oil BETAbsorption Absorption Mohr Salt Batch # (m²/g) pH (%) (%) TestT30-8-078-ARA 112 6.8 191 207 Green

The SEM photograph of this nano-composite (SAS &FCA) is shown in FIG.30. The graph of the XRD pattern of this nano-composite is shown in FIG.31.

Example 4—Novel Nano-Composite (SAS & FCA) Production

Step 1: Preparation of Synthetic Calcium Silicate Hydrate—Foshagite

This novel, multiphase calcium silicate hydrate of was formed by thesame hydrothermal reaction of lime and silica as described in Example 3.The reaction temperature was increased to 250° C., while the reactiontime was reduced to 2 hours. The sample was labeled T30-8-082. Theprocess conditions for preparation of material designated as batchT30-8-082 are given in Table 20. The pigment properties for materialsidentified as batch T30-8-082 are given in Table 21.

TABLE 20 Process conditions of Foshagite Formation (T30-8-082) Con-Reaction Raw Molar Ratio centration Temperature Time Batch # Material(CaO/SiO₂) (g/L) (° C.) (hours) T30-8-082 Ground 1.30 43 250 2 Quartz

TABLE 21 Properties of Foshagite (T30-8-082) Water Oil Absorption Batch# BET (m²/g) pH Absorption (%) (%) T30-8-082 37 11.7 234 231

The SEM photograph of this calcium silicate hydrate (foshagite) is shownin FIG. 32. The graph of the XRD pattern of this calcium silicatehydrate (foshagite) is shown in FIG. 33.

Step 2: Cogeneration of Nano-Composite (SAS & FCA) Having a StructuredAmorphous Silica Component and a Fibrous Crystalline Calcium CarbonateComponent, by Pressure Carbonation.

In this example seed material was added to the slurry. Other than thatthe process conditions were generally the same as set forth inExample 1. The sample ID was batch #T30-8-082-ARA. The processconditions for cogeneration are given in Table 22. The pigmentproperties of this nano-composite SAS & FCA material are given in Table23.

TABLE 22 Process Conditions of T30-8-082-ARA Start Final StartTemperature Temperature ΔT Pressure CO₂ Flow Rate Batch # (° C.) (° C.)(° C.) (bar) (L/min) T30-8- 60 70 10 4.8 112 082-ARA

TABLE 23 Properties of Nano-Composite (T30-8-082-ARA) Water Oil BETAbsorption Absorption Mohr Salt Batch # (m²/g) pH (%) (%) TestT30-8-082-ARA 171 6.9 211 220 Green

The SEM photograph of this nano-composite (SAS & FCA) is provided inFIG. 34. The graph of the XRD pattern of this nano-composite (SAS & FCA)is provided in FIG. 35.

In summary, an exemplary embodiment of a nano-composite (SAS & FCA) maybe manufactured in a straightforward manner. A synthetic calciumsilicate hydrate is provided. The selected synthetic crystalline calciumsilicate hydrate includes a base structure. Suitable synthetic calciumsilicate hydrate may include one or more of (a) xonotlite, (b)foshagite, (c) tobermorite, (d) riversidite, or other synthetic calciumsilicate hydrates. Currently, it is believed that the most costeffective results may be achieved by use of xonotlite; however, morework may reveal that products from other substrate starting syntheticcalcium silicate hydrates may be provide advantageous properties asdescribed herein. In various embodiments, the selected synthetic calciumsilicate hydrate is mixed with water, sodium hydroxide, and calciumhydroxide, to provide a slurry. The slurry is provided to a reactor. Inan embodiment, selected synthetic calcium silicate hydrate(s) may beprovided in the slurry in the range of from about 36 grams per liter toabout 120 grams per liter. In an embodiment, the selected syntheticcalcium silicate hydrate(s) may be provided in the slurry in the rangeof from about 48 grams per liter to about 96 grams per liter. 3 In anembodiment, the selected synthetic calcium silicate hydrate(s) may beprovided in the slurry in the range of from about 12 grams per liter toabout 600 grams per liter. In an embodiment, the ratio of CaO to SiO₂ inthe slurry may be in the range of from about 0.75 to about 1.3. Invarious embodiments, the reactor is pressurized, and carbonation of theselected synthetic crystalline calcium silicate hydrate proceeds byaddition of carbon dioxide or carbonic acid to the reactor whileagitating the contents of the reactor. In an embodiment, the pressure ofthe reactor may be in the range of from about 0.69 bar to about 20.68bar. In an embodiment, the pressure of the reactor may be in the rangeof from about 2.07 bar to about 6.89 bar. In an embodiment, the pressureof the reactor may be in the range of from about 3.45 bar to about 6.21bar. In an embodiment, the pressure of the reactor may be maintained atabout 4.83 bar. In an embodiment, the carbon dioxide may be provided tothe reactor as a gas. In various embodiments, the carbon dioxide may bepresent in the gas at from about 5% carbon dioxide, to about 100% carbondioxide. In an embodiment, the carbon dioxide may be present in the gasabout from about 10% to about 20%.

During reaction, calcium is extracted from the selected syntheticcalcium silicate hydrate that provides the base structure. Thus, theselected synthetic crystalline calcium silicate hydrate composition istransformed to silicon dioxide, thereby forming a fibrous amorphoussilica component. In various embodiments, the fibrous amorphous silicacomponent is provided in three-dimensional haystack configuration (mayalso be described as globular or pillow shaped) that presents a fibrousstructure having interstitial spaces between amorphous silica fiberswith inner layers and outer layers with irregular interlacing amorphoussilica fibers or filaments that are fixed in relation to each other.Such reaction proceeds under reaction conditions known to be conduciveto the formation of precipitated calcium carbonate in the form ofcrystalline aragonite. In an embodiment, the crystalline aragonite areattached to the fibrous amorphous silica component. Thus, anano-composite product is produced, wherein the nano-composite productincludes both fibrous structured amorphous silica and precipitatedcalcium carbonate in the form of fibrous crystalline aragonite. Invarious embodiments, the nano-composite product may have a major axis oflength L in the range from about 10 microns to about 40 microns, and asurface area of from about 40 meters squared per gram to about 200meters squared per gram. The reactor may be depressurized, preferablyafter reactants have been consumed to the extent feasible for theformation of the nano-composite material. Contents of the reactor maythen been cooled. In most applications, it may be necessary orconvenient to dry the nano-composite product produced in said reactor.

In various embodiments of a method for production of a nano-composite ofthe type set forth herein, the step of providing slurry may furtherinclude providing seed material. In an embodiment, such seed materialmay comprise aragonite. In various embodiments, such seed material maycomprise a previously manufactured portion of the nano-composite productitself. In an embodiment, the seed material may include one or moreselected synthetic calcium silicate hydrates. In various embodiments,the selected synthetic calcium silicate hydrates for use as seedmaterial may include one or more of (a) xonotlite, (b) foshagite, (c)tobermorite, and (d) riversidite. In an embodiment, the seed materialmay include calcium hydroxide (Ca(OH)₂) in the range of from about 2% toabout 10% by weight. In an embodiment, the seed material may includemagnesium hydroxide (Mg(OH)₂) in the range of from about 2% to about 10%by weight. In an embodiment, the seed material may include calciumhydroxide (Ca(OH)₂) in the range of from about 2% to about 10% byweight, and magnesium hydroxide (Mg(OH)₂) in the range of from about 2%to about 10% by weight, and wherein the ratio of magnesium hydroxide tocalcium hydroxide is in the range of from about 1:1 to about 2:1. In anembodiment, the seed material may include amorphous silica.

Applications for Nano-Composites (SAS & FCA) in Coatings

Process for Making Coatings

In an experimental apparatus, after a batch of nano-composite (SAS &FCA) material had been manufactured, validated, and approved by thetests described above, a slurry was then run through a 100 (152 micron)to 200 mesh (75 micron) screen to remove large particles, inertmaterial, and reactor scale. After the oversized material was removed,the slurry was then run through a series of unit operations to removethe excess water. In industrial practice, such processes may include useof a drum filter, and/or press filters, and/or vacuum filtration, and/orspray drying, and/or oven drying, or the like. In an embodiment, a dry,final product may be obtained. Such dry material may be ground up, e.gusing a ball mill or the like, so that the dried solid nano-compositematerial will pass through a screen of selected size, such as a 100 meshscreen.

High Solids Pigment Slurry

After a dry pigment sample was screened, it was then mixed with water tomake a high solids slurry with solids ranging from about 40% to about60%. That was accomplished with the use of a high shear mixer (such as aCowlez mixer or Silverson Unit). Before the dry pigment was mixed withthe water, a dispersing agent was added to the water (e.g., a sodiumpolyacrylamide). The amount of dispersing agent added per pound of drypigment may vary widely depending upon the selected dispersant, but forthe stated example, may range from about 0.5% to about 4%. The resultingslurry was passed through a 100 mesh screen to remove large agglomeratedparticles.

Coating Formulation—Pigment Mixing

Several different coating pigments may be combined to make a coatingformulation. Such coating pigments may include coating clays, calcinedclays, various forms of calcium carbonates, titanium dioxide, and othermaterials. Different coating pigments may be dispersed individually,either at the manufacturer's plant or the consumer's plant. The order ofmixing the various coating pigments is generally not too important, butcare should be taken to insure that agglomeration with differentpigments does not occur. With the different coating mixtures, thedispersed pigments described above were blended based on a parts method,by weight. Exemplary coating formulations are given in specific examplesset forth below.

After the various coating pigments were added to together, variousbinding agents were added to the blend. Some synthetic binding agentsmay include, but are not limited to, styrene-butadiene latex (“SBlatex”), styrene-acrylate latex, polyvinyl acetate, polyvinyl alcohol,vinyl acrylic latex, and vinyl acetate-ethylene latex. Also, naturalbinding agents may be selected from various materials such as cornand/or potato starches that have been modified, e.g., by enzymeconversion, or acid thinned, or cation protonated, or oxidized, orhydroxyethylated, or thermally modified, and/or turned into abiopolymer. Also, various soy proteins, modified by adding carboxylgroups, may be utilized.

After the final material components were added, the coating formulationwas screened through a selected screen, and in this embodiment, througha 100 mesh screen.

Thus, an exemplary coating composition for coating paper, paperboardproducts, or label stock may be provided by utilizing the nano-compositematerial described herein above. In various embodiments, exemplarycoating compositions may be provided using a water slurry including (a)a nano-composite material having a fibrous amorphous silica component,and a crystalline aragonite component. In an embodiment, the fibrousamorphous silica component may be provided in three-dimensional haystackor globular configuration that presents a fibrous structure havinginterstitial spaces between amorphous silica fibers, with inner layersand outer layers with irregular interlacing amorphous silica fibers orfilaments which are fixed in relation to each other. In an embodiment,the crystalline calcium carbonate component includes aragonite needlestructures. The aragonite needle structures arise from the fibrousamorphous silica component. Overall, in exemplary embodiments, thenano-composite material may have a major axis of length L in the rangefrom about 10 microns to about 40 microns, and a surface area of fromabout 40 meters squared per gram to about 200 meters squared per gram. Asuitable coating composition may also include clay, such as natural orcalcined clays, and one or more binders. In an embodiment, suitablebinders may include one or more latex compounds as generally known inthe art. In an embodiment, suitable binders may include one or moreprotein or protein derivative compounds as generally known in the art.Before use, a thoroughly mixed coating composition should be passedthrough a screen of selected size, to assure uniformity and absence ofoversize materials. In an embodiment, a 100 mesh screen may be suitable.In an embodiment for a coating composition, the amorphous silica fibersin the amorphous silica component may have a length of from about 3microns to about 4 microns. In an embodiment for a coating composition,the amorphous silica fibers in the amorphous silica component may havefibers with a diameter of about 10 nm. In an embodiment for a coatingcomposition, the amorphous silica fibers in the amorphous silicacomponent may have an aspect ratio of from about 50:1 to about 100:1. Inan embodiment for a coating composition, the aragonite needle structuresmay include aragonite crystals having a length of from about 1 micron toabout 10 microns. In an embodiment such aragonite crystals may have alength of from about 3 microns to about 5 microns. In an embodiment,such aragonite needle structures may include aragonite crystals having adiameter of from about 100 nm to about 200 nm. In an embodiment, thearagonite crystals may have an aspect ratio of from about 50:1 to about100:1. In various embodiments of a coating composition, suchnano-composite products may have a water absorption characteristic inthe range of from about 100% to about 300%. In various embodiments of acoating composition, such nano-composite products may have a waterabsorption characteristic of at least 150%. In various embodiments of acoating composition, such nano-composite products may have an oilabsorption characteristic in the range of from about 150% to about 300%.In various embodiments of a coating composition, such nano-compositeproducts may have an oil absorption characteristic in the range of fromabout 200% to about 250%. In various embodiments of a coatingcomposition, such nano-composite products may have a surface area in therange of from about 50 meters squared per gram to about 150 meterssquared per gram.

In various embodiments, a suitable coating composition may furtherinclude ground calcium carbonate. In various embodiments of a coatingcomposition, such nano-composite products may further include at leastsome titanium dioxide. In various embodiments of exemplary coatingcompositions as set forth herein, an increase in the amount of saidnano-composite material in the coating composition may allow decrease inthe quantity of said titanium dioxide necessary to be used in saidcoating composition, in order to achieve desired properties such asbrightness or opacity. For example, in a selected coating composition,wherein as a base case a specific target brightness may be achieved withselected amount of titanium dioxide in the absence of nano-compositematerial, it may be noted that such specific target brightness may alsobe achieved by replacement of up to 75% of the selected amount oftitanium dioxide by addition of an effective amount of thenano-composite material in the coating composition. Similarly, in aselected coating composition, wherein as a base case a specific targetbrightness may be achieved with selected amount of titanium dioxide inthe absence of said nano-composite material, it may be noted that suchspecific target brightness may also be achieved by replacement of 50% ofthe selected amount of titanium dioxide by addition of an effectiveamount of the nano-composite material. Similarly, in a selected coatingcomposition, wherein as a base case a specific target brightness may beachieved with selected amount of titanium dioxide in the absence of saidnano-composite material, it may be noted that such specific targetbrightness may also be achieved by replacement of 25% of the selectedamount of titanium dioxide by addition of an effective amount of thenano-composite material. More generally, it can be said that in manycases where a coating composition further includes any one or more of(a) titanium dioxide, (b) calcined clay, (c) natural clay, and (d)ground calcium carbonate, and providing an effective amount of thenano-composite material in the coating composition may allow a decreasein the quantity of a selected one or more of (a) titanium dioxide, (b)calcined clay, (c) natural clay, and (d) ground calcium carbonate, inthe coating composition, as necessary to meet selected performance orcost objectives.

In must further be noted that the nano-composite (SAS & FCA) materialdescribed herein may have, in many cases, beneficial attributes tocoating formulations, generally. In an embodiment the nano-compositematerial comprises a viscosity modifier. In an embodiment, thenano-composite material comprises an immobilization time reduction agentin a coating composition. In an embodiment, the nano-composite materialcomprises a surface strength improvement agent in a coating composition,as measured by IGT pick test results. In an embodiment, thenano-composite material comprises a blister resistance improvement agentin a coating composition, as measured by IGT blister test results. In anembodiment, the nano-composite material comprises an appearanceimprovement agent. In an embodiment, the nano-composite materialcomprises a surface smoothness improvement agent in a coatingcomposition, as measured by Parker Print Smoothness testing. In anembodiment, the said nano-composite material comprises a whiteness (“L”value) improvement agent in a coating composition. In an embodiment, thenano-composite material comprises a green shade (“a” value) improvementagent in a coating composition. In an embodiment the nano-compositematerial comprises a blue-white shade improvement agent in a coatingcomposition. In an embodiment, the nano-composite material comprises asurface finish agent, in a coating composition, whereby a low glossmatte finish may be provided in a coated sheet. In an embodiment, thenano-composite material comprises a caliper enhancing constituent in acoating composition, wherein a coated sheet of increased caliper isprovided.

In various embodiments, an exemplary coating composition may be providedby using the combination of a novel nano-material (SAS & FCA) and aselected synthetic calcium silicate hydrate. In an embodiment, anexemplary selected synthetic calcium silicate hydrate includesaragonite.

Coating Application

After the coating formulations were made, a coating was then applied toa substrate/base in one of several methods. These methods included airknife, rod, blade, and other coating methods. In the lab, a lab rodcoater (RK Control Coater) was used. After the coating is applied basedon the end-user's requirements, the coated sample was dried, generallyusing a heated drum (Regal-Arkay ST-22). After the coating was dried,the resulting coated sample was examined for defects or gaps in thecoating.

Testing of Coated Material

When a sample coating passed initial examination as just noted above, itwas then tested for the following properties:

-   (1) Brightness;-   (2) L—Value;-   (3) a—Value;-   (4) b—Value;-   (5) Gloss;-   (6) Opacity (if applicable);-   (7) Scattering Power;-   (8) Absorption Power;-   (9) Smoothness/Roughness;-   (10) Appearance (APT, DAV 1, DAV 2, DMM);-   (11) IGT Pick;-   (12) IGT Blister; and-   (13) Caliper.

Coating of Unbleached Board

A coating operation was conducted at a laboratory in Tacoma, Wash. Thepigment slurries were dispersed using a Silverson disperser thenscreened through a 100 mesh screen. Coating binders were added to thepigment slurry, first a soybean based protein followed by a latex, andthe coating formulation was blended with a Silverson low shear mixer.The coatings were applied to the paperboard using a RK rod coater anddried in a drum dryer having a Teflon coated, non-stick surface (RegalArkey ST-22). Coatings were applied over a range of coat weights andthen soft nip calendared. The test data for each coating condition,including the lab control, were plotted as a function of coat weight andnormalized to a target coat weight for comparison.

Example 5—Unbleached Board Coating, Top Coat Only

For Example 5, an unbleached Kraft paperboard having a production basecoating was as a substrate on which a top coating was applied in thelaboratory. The TiO₂ range for the top coat control was in the 15 partsto 20 parts range per 100 parts of total dry pigment (by weight), whichincluded calcined clay and #1 coating clay, with soybean based proteinand SB Latex as binder. In this case study, 25%, 50%, and 75% of theTiO₂ was replaced with a nano-composite (SAS & FCA) material in thecoating formulation. The coating formulation is given below in Table 24.

TABLE 24 Coating Formulation for Top Coat Dry Parts (By Weight)Material/Order 25% Nano- 50% Nano- 75% Nano- of Addition ControlComposite Composite Composite #1 High Brightness 64 64 64 64 CoatingClay TiO₂ 20 15 10 5 Calcined Clay 16 16 16 16 Nano-Composite 0 5 10 15SAS & FCA Total Pigment 100 100 100 100 Soybean Based 5 5 5 5 Protein SBLatex 15 15 15 15 Total Binder 20 20 20 20 Total Pigment + 120 120 120120 Binder

The high surface area, high aspect ratio, and low bulk density of priorart materials similar to the tested nano-composite (SAS & FCA) generallyresults in a high binder demand, high viscosity, higher immobilizationtime, and low pick strength. However, it was surprising to find just theopposite results with respect to the tested nano-composite (SAS & FCA)material. One of the unique characteristics of the nano-composite (SAS &FCA) material described herein was that it performed equal or betterthan the TiO₂ containing control formulation. FIG. 36 is a plot ofBrookfield viscosity over a solids range of 30% to 50% for both the TiO₂control and the use of the nano-composite (SAS & FCA) based coating, andshows that in the 40% to 45% solids range, where an air knife coaterwould most likely operate, we see that the viscosities are nearlyidentical. Thus, it is anticipated that such a coating compositionincluding the novel nano-composite (SAS & FCA) may be utilized as adrop-in substitution in some coating applications.

Coating immobilization study results are shown in FIG. 37. The testswere performed using a Dynamic Water Retention (DWR) device. FIG. 37shows how long it takes for the coating to immobilize. There is adistinguishable difference between the control coating with TiO₂ and thenano-composite (SAS & FCA) based coatings. The data shows that thenano-composite (SAS & FCA) based coatings have a much fasterimmobilization rate as compared to the control TiO₂ coatings.

The coated sheets were soft-nip calendared to a target Parker PrintSmoothness of 3.0 (PPS 10S). The calendared sheets were then tested asper the protocol described above. The test results are given in Table25. Then the test data was plotted as a function of coat weight andnormalized to a target coat weight of 17 to 19 grams per square meterfor comparison.

The IGT Pick strength and IGT Blister, shown in FIGS. 38 and 39,respectively, show the coating strength for the nano-composite (SAS &FCA) is significantly better (28% and 33% respectively) than the TiO₂control. It is believed silanol bonding sites may play a role in thisstrength improvement, which could potentially translate into a lowerbinder demand.

The APT Appearance test, shown in FIG. 40, shows that the nano-composite(SAS & FCA) based coating coverage is comparable to the TiO₂ control.

The ISO Brightness of the nano-composite (SAS & FCA) based coating wasseveral points lower than the TiO₂ control, as indicated in FIG. 41.However, such characteristics do offer an advantage for reducing dyecosts where dye-back methods are sometimes used to improve appearance.

Parker Print Smoothness (10S) showed comparable results (FIG. 42).

The “L” value (whiteness) showed a slight drop with the addition of thenano-composite (see FIG. 43).

The “a” value (red-green color balance) showed a slight shift of thecoating color to the red (see FIG. 44).

The “b” value (yellow-blue color balance) showed a significant shift toa blue-white shade (see FIG. 45).

TABLE 25 Coating Performance - For Top Coat 25% 50% 75% Nano- Nano-Nano- Control Composite Composite Composite ISO Brightness 79.71 78.9078.20 78.11 % Difference from Control −1.0% −1.9% −2.0% MD Gloss 27.623.3 21.5 20.7 % Difference from Control −15.5% −21.9% −25.0% CD Gloss26.9 23.1 21.1 20.1 % Difference from Control −14.3% −21.5% −25.5% LValue 90.87 90.50 90.10 89.71 % Difference from Control −0.4% −0.8%−1.3% a Value −2.42 −2.13 −1.98 −2.01 % Difference from Control −12.1%−18.0% −17.0% b Value −0.29 −0.66 −0.84 −0.63 % Difference from Control−37.3% 188.4% 115.3% IGT Pick 64.2 72.4 76.1 81.6 % Difference fromControl 12.9% 18.5% 27.2% IGT Blister 63.7 66.1 70.7 83.9 % Differencefrom Control 3.8% 10.9% 31.7% AGT Appearance 6.51 7.51 7.32 6.23 %Difference from Control −15.4% −12.5% 4.2% PPS Roughness 2.9 2.9 2.8 3.0% Difference from Control −1.4% 3.1% −5.0% Caliper 14.4 14.6 14.6 14.6 %Difference from Control 1.1% 1.1% 1.4% Bulk 1.31 1.31 1.30 1.32 %Difference from Control −0.4% −1.0% 0.7%

The gloss of the sheets coated with the nano-composite (SAS & FCA) basedcoating showed a shift towards a matte finish in both the machinedirection (MD) and cross direction (CD), as seen in FIGS. 46 and 47,respectively.

The addition of the nano-composite (SAS & FCA) in the coatingformulation did increase the caliper, as shown in FIG. 48. Coatedpaperboard samples were sent to Nancy Plowman Associates for printtesting to understand the potential print performance of the variousnano-composite (SAS & FCA) based coatings as compared to the TiO₂control. For the print tests performed, the print results, Table 26,indicated the nano-composite (SAS & FCA) based coating was comparable tothe TiO₂ control.

TABLE 26 Print Testing Results 75% Nano-Composite Sample TiO₂ Control(SAS & FCA) P&I Slope 23.7-25.9 18.6-19.5 (g/cm/sec) Pass to Fail 6 6 %Transfer 94 94 % Wet Pick 0 5 Mottle Rating 5 5

The criteria for the above noted tests are given below:

Slope: The higher the slope the faster the coated surface can remove thethin oils from an ink.

Pass to Fail: Four passes or less indicates possible picking on anoffset press.

% Transfer: A higher percentage means better fountain solutionabsorption. 60%+ is excellent.

% Wet Pick: A wet pick of <25% is excellent.

Mottle Rating: This test by itself does not predict mottle on press. Itonly shows absorption uniformity and a value of 1=excellent and 5=poor.

Example 6—Unbleached Kraft Paper Board—Base Coating and Top Coating

Example 6 used an unbleached Kraft paperboard, which was base coatedwith a 75/25 blend of aragonite S-PCC and nano-composite (SAS & FCA).Together, these two components completely replaced the #2 clay that hadbeen utilized in the base coating control formulation. The base coatweight target was 14 to 16 grams per square meter. The top coating was a65/35 blend of aragonite S-PCC and nano-composite (SAS & FCA) at a topcoat weight target of 17 to 20 grams per square meter. Both basecoatings used the same blend of soybean based protein and SB latex. Bothtop coatings used the same blend of soybean based protein and SB latex.Finally, the coated sheets were soft-nip calendared to a target ParkerPrint Smoothness (PPS 10S) of 3.0.

TABLE 27 Coating Formulations for Unbleached Kraft Paperboard BaseCoating: Top Coating: Dry Parts (weight) Dry Parts (weight)Coating/Order of 100% 100% Addition Control Replacement ControlReplacement #2 Coating Clay 100 0 NA NA Aragonite S-PCC 0 75 0 63Nano-Composite 0 25 0 37 (SAS & FCA) #1 High Brightness NA NA 64 0Coating Clay TiO2 NA NA 20 0 Calcined Clay NA NA 16 0 Total Pigment 100100 100 100 Soybean Based Protein 3 3 5 5 SB Latex 14 14 15 15 TotalBinder 17 17 20 20 Total Pigment + Binder 117 117 120 120

TABLE 28 Coating Performance Results Unbleached Kraft Paperboard 100%Control Replacement ISO Brightness 79.71 82.96 % Difference from Control4.1% L Value 90.87 88.56 % Difference from Control −2.5% a Value −2.42−0.16 % Difference from Control −93.4% b Value −0.29 −0.59 % Differencefrom Control 101.6% IGT Pick 64.2 111.0 % Difference from Control 73.0%IGT Blister 63.7 92.0 % Difference from Control 44.4% AGT Appearance6.51 8.16 % Difference from Control 25.4%

Findings:

IGT Pick strength and IGT Blister resistance, as indicated in FIGS. 49and 50, respectively, showed a significant improvement (73% and 44%respectively) for the coating composition utilizing (1) aragonite superprecipitated calcium carbonate (S-PCC) and (2) nano-composite (SAS &FCA) based coating, over the control coating. The nano-composite (SAS &FCA) structures, as indicated in the photomicrograph illustrated inFIGS. 2 and 6, may retain a hollow macrosphere structure sized andshaped similar to the size and shape of a synthetic calcium silicatehydrate used as a raw material. For example, compare FIGS. 2 and 6(nano-composite (SAS & FCA) with the structures seen in selectedsubstrate calcium silicate hydrates that may be utilized as substratesfor the production of nano-composite (SAS & FCA), as indicated in FIG.12, 14, 16, or 18. In any event, the surface strength improvement offersan opportunity to reduce binder demand, when the novel coatingformulations including nano-composite (SAS & FCA) materials areutilized.

The APT Appearance was slightly better for the control, as noted in FIG.51. However, the ISO Brightness showed a distinct improvement, when 100%of the TiO₂ was replaced by the nano-composite (SAS & FCA), as indicatedin FIG. 52.

The “L” value (whiteness) showed a slight drop when 100% of the TiO₂ wasreplaced with nano-composite (SAS & FCA); see FIG. 53.

The “a” value (red-green color balance) showed a shift of the coatingcolor to the red when 100% of the TiO₂ was replaced with nano-composite(SAS & FCA); see FIG. 54.

The “b” value (yellow-blue color balance) showed a significant shift toa blue-white shade when 100% of the TiO₂ was replaced withnano-composite (SAS & FCA); see FIG. 55.

Coating of Label Stock

Example 7—Label Stock Paper Coating—High Basis Weight Single Coat

In this example, a bleached, uncoated, wood-free sheet with a basisweight of 70 grams per square meter was used. As shown in Table 29, thecontrol coating was made up of 64 dry parts (by weight) of #1 highbrightness clay (supplied by Theile), 8 parts (by weight) calcined clay(also supplied by Theile), and 24 parts (by weight) Ground CalciumCarbonate (supplied by OMYA). The remaining 4 parts (by weight) of thecoating was made up of TiO₂ (supplied by DuPont). Novel coatingformulations that were tested were identified as “condition 1”, or as“condition 2”, or as “condition 3”. In various embodiments, coatingformulations included pigments that contained mostly the novelnano-composite structured amorphous silica (SAS) and nano fibrouscrystalline aragonite calcium carbonate (FCA). In various embodiments,some of the coating compositions also included calcium silicate hydrate(foshagite CSH from GR Nano Materials, Tacoma, Wash., USA) (3 parts) andAragonite S-PCC (from GR Nano Materials, Tacoma, Wash., USA) (3 parts);all parts are by weight. Binder in the form of 15.5 parts of SBIR Latexwas added with constant stirring to a coating formulation mixture insome embodiments. In various embodiments, the coating formulation slurrywas thoroughly mixed in a Silverson unit for 5 minutes. The thoroughlymixed coating formulations were screened through a screen of selectedsize, normally through a 100 mesh screen, to provide a finished coatingcomposition ready for use. Thus 100% of the TiO2 (only 4 parts) wasreplaced by GR Nano Materials pigments with 6 parts (by weight) of GRNano Materials products, which alternately was by (1) a mixture ofcalcium silicate hydrate (foshagite CSH) and nan-composite (SAS & FCA),or (2) by a mixture of calcium silicate hydrate (foshagite CSH) andaragonite S-PCC, or (3) by calcium silicate hydrate (foshagite CSH)alone.

Table 29 shows the blend procedure and composition utilized for thecoating formulations utilized in the embodiments set out in thisexample. The actual coating and drying of the samples was carried outthe same as described above. As per the testing profile, the coatedsheets were tested for TAPPI Opacity, ISO Opacity as well as scatteringcoefficient and absorption coefficient (see Table 30).

TABLE 29 Coating Formulations - for High Basis Weight Label Stock DryParts (by weight) Condition Condition Condition Material/Order ofAddition Control 1 2 3 #1 High Brightness 64.0 62.0 62.0 62.0 CoatingClay Calcined Clay 8.0 8.0 8.0 8.0 Ground Calcium Carbonate 24.0 24.024.0 24.0 TiO₂ 4.0 0.0 0.0 0.0 Calcium Silicate Hydrate 0.0 3.0 3.0 6.0(CSH) Foshagite Nano-Composite 0.0 3.0 0.0 0.0 (SAS & FCA) AragoniteS-PCC 0.0 0.0 3.0 0.0 Total Pigment 100.0 100.0 100.0 100.0 Latex 15.515.5 15.5 15.5 Total Binder 15.5 15.5 15.5 15.5 Total Pigment + Binder115.5 115.5 115.5 115.5

TABLE 30 Coating Formulation Performance - High Basis Weight Label StockCondition Condition Condition Control 1 2 3 TAPPI Opacity 86.8 86.5 86.786.6 % Difference from Control −0.4% −0.2% −0.3% ISO Opacity 88.8 88.388.4 88.2 % Difference from Control −0.6% −0.5% −0.7% ScatteringCoefficient 704.3 696.4 701.4 687.9 % Difference from Control −1.1%−0.4% −2.3% Absorption Coefficient 3.6 3.2 3.2 3.3 % Difference fromControl −11.2% −10.8% −9.5%

Findings:

One finding was that it appears that 100% of the titanium dioxide (TiO₂)in such coating formulations can be replaced, either by a combination ofthe nano-composite (SAS & FCA) with a calcium silicate hydrate (CSH)(condition 1), or by a calcium silicate hydrate (CSH) alone (condition3), or by a combination of calcium silicate hydrate and aragonite S-PCC(condition 2). See Tables 29 and 30. Also, FIGS. 56 and 57 show theresults of TAPPI Opacity and ISO Opacity, respectively, for the highbasis weight label stock coated paper samples.

Example 8—Label Stock, Low Basis Weight, High TiO₂ Coating

The coating formulation utilized in Example 8 was generally prepared asset forth in Example 7. However, the label stock paper had a basisweight of 67 grams per square meter of paper. Also, the amounts utilizedfor the different coating pigments were changed, as shown in Table 31.The making of the coating and the testing of the sheets was generallythe same as set forth in Example 7. Table 32 shows the results ofopacity testing.

TABLE 31 Coating Formulations - for Low Basis Weight Label Stock DryParts (by weight) Condition Condition Condition Material/Order ofAddition Control 1 2 3 #1 High Brightness Coating 50.0 44.0 44.0 44.0Clay Calcined Clay 10.0 10.0 10.0 10.0 Ground Calcium Carbonate 28.028.0 28.0 0.0 TiO2 12.0 0.0 6.0 6.0 Calcium Silicate Hydrate 0.0 9.0 6.012.0 (CSH) - Foshagite Nano-Composite 0.0 9.0 0.0 0.0 (SAS & FCA)Aragonite S-PCC 0.0 0.0 6.0 28.0 Total Pigment 100.0 100.0 100.0 100.0Latex 16.5 16.5 16.5 16.5 Total Binder 16.5 16.5 16.5 16.5 TotalPigment + Binder 116.5 116.5 116.5 116.5

TABLE 32 Coating Performance - Low Basis Weight Label Stock ConditionControl Condition 1 Condition 2 3 TAPPI Opacity 87.9 86.6 86.9 87.8 %Difference −1.5% −1.1% −0.1% from Control ISO Opacity 89.5 88.6 88.589.3 % Difference −1.0% −1.2% −0.3% from Control Scattering Coefficient797.7 731.1 651.5 694.0 % Difference −8.3% −18.3% −13.0% from ControlAbsorption Coefficient 4.9 5.1 4.4 4.4 % Difference 4.3% −10.6% −9.4%from Control

Findings:

As seen in FIG. 59 (see also Tables 31 and 32), one finding was that inan embodiment, 50% of the titanium dioxide (TiO₂) may be replaced by thecombination of 12.0 parts (by weight) of a foshagite calcium silicatehydrate (CSH) and aragonite (S-PCC). FIGS. 58 and 59 show the results ofTAPPI Opacity and ISO Opacity, respectively. While the use of thecombination of nano-composite (SAS & FCA) with a foshagite calciumsilicate hydrate (CSH) did not yield the desired opacity, the data showsthat by replacing the GCC with aragonite S-PCC (see condition 3), it maybe possible to replace 50% of the TiO₂.

In summary, it can be appreciated that an exemplary coated board,paperboard, or label stock paper may be produced by utilizing novelcoating formulations as described above. In an embodiment, a coated,calendared, paperboard may be provided having (a) one or more layers ofpulp (which may in an embodiment be kraft pulp, and may, in anembodiment, be unbleached kraft pulp), and (b) a base coatingcomposition. The base coating composition may include a nano-compositematerial having a fibrous amorphous silica component and a crystallinecalcium carbonate component. In an embodiment, the fibrous amorphoussilica component may be provided in three-dimensional haystack orglobular configuration that presents a fibrous structure havinginterstitial spaces between amorphous silica fibers with inner layersand outer layers with irregular interlacing amorphous silica fibers orfilaments which are fixed in relation to each other. The crystallinecalcium carbonate component, may be provided in the form of acrystalline calcium carbonate in the aragonite phase, having needlestructures. The aragonite needle structures may arise from the fibrousamorphous silica component. The nano-composite material may have a majoraxis of length L in the range from about 10 microns to about 40 microns,and a surface area of from about 40 meters squared per gram to about 200meters squared per gram. The base coating composition may also includeclay, either natural or calcined, or both. The base coating compositionmay include one or more binders as known in the field, such as aselected latex, and/or a selected protein.

In an embodiment, a coated, calendared paperboard as just set forthabove may also include a top coating. In an embodiment, the top coatingmay include a nano-composite material having a fibrous amorphous silicacomponent and a crystalline calcium carbonate component. In anembodiment, the fibrous amorphous silica component may be provided inthree-dimensional haystack or globular configuration that presents afibrous structure having interstitial spaces between amorphous silicafibers with inner layers and outer layers with irregular interlacingamorphous silica fibers or filaments which are fixed in relation to eachother. The crystalline calcium carbonate component, may be provided inthe form of a crystalline calcium carbonate in the aragonite phase,having needle structures. The aragonite needle structures may arise fromthe fibrous amorphous silica component. The nano-composite material mayhave a major axis of length L in the range from about 10 microns toabout 40 microns, and a surface area of from about 40 meters squared pergram to about 200 meters squared per gram. The top coating compositionmay also include clay, either natural or calcined, or both. The basecoating composition may include one or more binders as known in thefield, such as a selected latex, and/or a selected protein.

In various embodiments, a coated, calendared paperboard as just setforth above may have an IGT Pick of at least 100. In variousembodiments, a coated, calendared paperboard as just set forth above mayhave an IGT Blister of least 92. In various embodiments, a coated,calendared paperboard as just set forth above may have an AGT Appearanceof at least 8. In various embodiments, a coated, calendared paperboardas just set forth above may have an ISO Opacity of at least 88.0. Invarious embodiments, a coated, calendared paperboard as just set forthabove may have a Tappi Opacity of at least 86.0. Yet more generally, apaper may be provided have a coating composition as set forth herein.Similarly, a paperboard may be provided have a coating composition asset forth herein. Even more generally, novel compositions of matter aredescribed herein, in the specification, or in the drawing figures, orboth. Methods are described for manufacture of such compositions ofmatter. And, methods for use of such compositions of matter aredescribed.

In the foregoing description, numerous details have been set forth inorder to provide a thorough understanding of the disclosed exemplaryembodiments for providing novel nano-composite materials. However,certain of the described details may not be required in order to provideuseful embodiments, or to practice selected or other disclosedembodiments. Further, the description may include, for descriptivepurposes, various relative terms such as approximately, about, surface,adjacent, proximity, near, on, onto, and the like. Such usage should notbe construed as limiting. Terms that are relative only to a point ofreference are not meant to be interpreted as absolute limitations, butare instead included in the foregoing description to facilitateunderstanding of the various aspects of the disclosed embodiments.Various items in the apparatus and in the method(s) described herein mayhave been described as multiple discrete items, in turn, in a mannerthat is most helpful in understanding such aspects and details. However,the order of description should not be construed as to imply that suchitems or sequence of operations are necessarily order dependent, or thatit is imperative to fully complete one step before starting another. Forexample, the choice of raw materials utilized may depend on a variety ofcost and use factors, and such decisions may be different as regardsinstallation particulars amongst various locales for production, orvarious end users, or various end use products. Further, certain detailsof manufacture may not need to be performed in the precise or exactorder of presentation herein. And, in different embodiments, one or moreitems may be performed simultaneously, or eliminated in part or in wholewhile other items may be added. Also, the reader will note that thephrase “an embodiment” has been used repeatedly. This phrase generallydoes not refer to the same embodiment; however, it may. Finally, theterms “comprising”, “having” and “including” should be consideredsynonymous, unless the context dictates otherwise.

Various aspects and embodiments described and claimed herein may bemodified from those shown without materially departing from the novelteachings and advantages provided by the developments described herein,and may be embodied in other specific forms without departing from thespirit or essential characteristics thereof. Embodiments presentedherein are to be considered in all respects as illustrative and notrestrictive or limiting. This disclosure is intended to cover methodsand compositions described herein, and not only structural equivalentsthereof, but also equivalent structures. Modifications and variationsare possible in light of the above teachings. Therefore, the protectionafforded to the developments described herein should be limited only bythe claims set forth herein, and the legal equivalents thereof.

I claim:
 1. A composition of matter, comprising: a nano-compositestructure having (a) a fibrous amorphous silica component, said fibrousamorphous silica component provided in three-dimensional haystackconfiguration that presents a fibrous structure having interstitialspaces between amorphous silica fibers with inner layers and outerlayers with irregular interlacing amorphous silica fibers or filamentswhich are fixed in relation to each other; (b) a crystalline calciumcarbonate component, said crystalline calcium carbonate componentcomprising aragonite needle structures, said aragonite needle structuresarising from said fibrous amorphous silica component; and (c) whereinsaid nano-composite structure has a major axis of length L in the rangefrom about 10 microns to about 40 microns, and a surface area of fromabout 40 meters squared per gram to about 200 meters squared per gram.2. The composition of matter as set forth in claim 1 wherein saidamorphous silica fibers have a length of from about 3 microns to about 4microns.
 3. The composition of matter as set forth in claim 1, whereinsaid amorphous silica fibers have a diameter of about 10 nm.
 4. Thecomposition of matter as set forth in claim 1, wherein said amorphoussilica fibers have an aspect ratio of from about 50:1 to about 100:1. 5.The composition of matter as set forth in claim 1 wherein said aragoniteneedle structures comprise aragonite crystals having a length of fromabout 1 micron to about 10 microns.
 6. The composition of matter as setforth in claim 5, wherein said aragonite crystals have a length of fromabout 3 microns to about 5 microns.
 7. The composition of matter as setforth in claim 1, wherein said aragonite needle structures comprisearagonite crystals having a diameter of from about 100 nm to about 200nm.
 8. The composition of matter as set forth in claim 7, wherein saidaragonite crystals have an aspect ratio of from about 50:1 to about100:1.
 9. The composition of matter as set forth in claim 1, whereinsaid composition has a water absorption characteristic in the range offrom about 100% to about 300%.
 10. The composition of matter as setforth in claim 1, wherein said composition of matter has a waterabsorption characteristic of at least 100%.
 11. The composition ofmatter as set forth in claim 1, wherein said composition of matter hasan oil absorption characteristic in the range of from about 150% toabout 300%.
 12. The composition of matter as set forth in claim 1,wherein said composition of matter has an oil absorption characteristicin the range of from about 200% to about 250%.
 13. The composition ofmatter as set forth in claim 1, wherein said composition of matter hassurface area in the range of from about 50 meters squared per gram toabout 150 meters squared per gram.
 14. The composition of matter as setforth in claim 1, further characterized in that when mixed with water,the pH is in the range of from about 6.5 to about 7.5.
 15. Thecomposition of matter as set forth in claim 1, further characterized inthat in an X-ray diffraction of said composition of matter, a major peakfor aragonite appears at approximately 3.22 angstroms.